In This Issue

Different brain atrophy in Down syndrome with Alzheimer disease (ADNC) compared to Alzheimer disease with related neurogenerative pathologies (ADRNP)

Liou et al compared regional brain volumes from ante- and postmortem imaging to neurodegenerative neuropathology in autopsy brains from 12 Down syndrome (DS) and 54 ADRNP cases which included 16 ADNC only cases. They report that LATE-NC significantly influenced hippocampal and amygdala volumes in ADRNP. However, since LATE-NC was uncommon in DS, hippocampal and amygdala volumes were influenced more by tau pathology.

page 364

Pineal solitary fibrous tumors (SFTs)

Robins et al report on five SFTs in the pineal region, along with a literature review of additional cases. They remind pathologists to include this tumor type in their differential diagnosis of pineal region tumors. Interestingly, in one of the cases with metastasis to the lung, a NAB2::STAT6 fusion was not identified in either the original pineal tumor or the second recurrence despite high STAT6 expression. The authors review differing NAB2::STAT6 fusion transcripts that have been described and report that up to 12% of SFTs may lack a NAB2::STAT6 fusion.

page 379

A new way of looking at nerve biopsies

Although three-dimensional microscopy can provide important new information when evaluating pathology in specimens such as peripheral nerve biopsies, actually performing it has been challenging. Adamian et al describe a simple post-hoc dimension reduction approach known as maximum intensity projection and demonstrate its application to peripheral nerve. The authors also provide a user-friendly open-source algorithm to encourage adoption of this technique.

page 391

More than just amyloid in meningeal cerebral amyloid angiopathy (CAA)

Leptomeningeal vessel walls are frequently involved in CAA and may be the source of associated hemorrhages. Sigurdson et al report that analysis of these vessel walls shows that there are increases in a minor heparan sulfate disaccharide, an unsubstituted glucosamine, as well as 6-O sulfated disaccharides. There was also an increase in specific extracellular proteins derived from brain parenchyma or serum. Interactions of these proteins with Aβ deposits may play an important role and help in contributing to the development of antemortem diagnostic assays and possible therapeutic interventions.

page 398

Regional astrogliosis differences in hepatic encephalopathy (HE)

Ouard et al report on significant regional differences in GFAP positive astrogliosis between cortical and subcortical regions including the corpus callosum white matter in a rodent model of HE. Overall, they found areas with increased as well as decreased astrogliosis and suggest either different regional reactive responses and/or different stages of progression of astroglial reaction in HE.

page 412

White matter (WM) oligodendrocytes (OL) following traumatic brain injury (TBI)

To understand mechanisms of long-term degenerative processes that result in impaired cognition following TBI, Rauscher et al analyzed expression of the myelin-associated axonal outgrowth inhibitor Nogo-A in acute and chronic TBI in WM in cases of human postmortem TBI and in a mouse model of central fluid percussion injury. They observed increased numbers of Nogo-A⁺ cells and decreased numbers of mature OL in WM tracts. These persisted for long terms in the mice. Their data indicate that persistent vulnerability of OL in combination with dynamic alterations of Nogo-A expression underlie WM atrophy and insufficient functional recovery following TBI.

page 423