Limbic-Predominant Age-Related TDP-43 Encephalopathy

Abstract

Background and Objectives:Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is present in ∼25% of older persons’ brains and is strongly associated with cognitive impairment. Hippocampal sclerosis (HS) pathology is often comorbid with LATE-NC, but the clinical and pathological correlates of HS in LATE-NC are not well understood.Methods:In this retrospective autopsy cohort study, data derived from the National Alzheimer’s Coordinating Center (NACC) Neuropathology Data Set, which included neurological status, medical histories, and neuropathologic results. All autopsies were performed in 2014 or later. Among participants with LATE-NC, those who also had HS pathology were compared with those without HS with regard to candidate risk factors or common underlying diseases. Statistical significance was set at nominal p<0.05 in this exploratory study.Results:A total of 408 participants were included (n=221 were LATE+/HS-; n=145 were LATE+/HS+, and n=42 were LATE-/HS+). Most of the included LATE-NC+ participants were severely impaired cognitively (83.3% demented). Compared to HS- participants, LATE-NC+ participants with HS trended towards having worse cognitive status and scored lower on the “Personal Care” and “Orientation” domains (both p=0.03). Among LATE-NC+ participants with Braak NFT Stages 0-IV (n=88), HS+ participants were more impaired in the “Memory” and “Orientation” domains (both p=0.02). There were no differences (HS+ compared with HS-) in the proportion with clinical histories of seizures, stroke, cardiac bypass procedures, diabetes, or hypertension. The HS+ group lacking TDP-43 proteinopathy (n=42) were relatively likely to have had strokes (p=0.03). Comparing LATE-NC+ participants with or without HS, there were no differences in Alzheimer’s disease neuropathologies (Thal Aβ phases or Braak NFT stages) or Lewy body pathologies. However, the HS+ group was less likely to have amygdala-restricted TDP-43 proteinopathy (LATE-NC Stage 1) and more likely to have neocortical TDP-43 proteinopathy (LATE-NC Stage 3); p<0.001. LATE-NC+ brains with HS also tended to have more severe Circle of Willis atherosclerosis and arteriolosclerosis pathologies.Discussion:In this cohort skewed toward severely demented participants, LATE-NC+HS pathology was not associated with seizures or with Alzheimer’s-type pathologies. Rather, the presence of comorbid HS pathology was associated with more widespread TDP-43 proteinopathy, and with more severe non-Aβ vessel wall pathologies.

A novel histological staging of hippocampal sclerosis that is evident in gray matter loss in vivo

“…26 Previous studies have employed differing criteria to evaluate vascular pathology, resulting in conflicting results on its relation with HS. 5,12,34,[37][38][39][40] Despite this lack of consensus, our results support the reported association of arteriolosclerosis with HS, 41,42 as well as with LATE. 43,44 A future consensual evaluation of α-synuclein and vascular pathologies throughout several cohorts would aid the clear delimitation of their relationship with HS progression.…”

A novel histological staging of hippocampal sclerosis that is evident in grey matter lossin vivo

“…Despite this lack of consensus, our results support the reported association of arteriolosclerosis with HS 41,42 , as well as with LATE 43,44 . A future consensual evaluation of α-synuclein and vascular pathologies throughout several cohorts would aid the clear delimitation of their relationship with HS progression.…”

“…(A) amygdala and anterior entorhinal cortex (section corresponding to levels 24-27 of the microatlas by Mai et al 30 ), (B) hippocampal head (levels [32][33][34][35], and (C) hippocampal body immediately posterior to the tip of the uncus (levels [39][40][41][42][43]. Five stages of HS were defined based on qualitative evaluation of H/E histological sections from blocks (B) and (C), resulting in stages at the hippocampal head and body, respectively.…”

When Alzheimer's isLATE: Why Does it Matter?

“…For example, in 678 subjects from the UK‐ADRC cohort (panel C), among those with autopsy proven HS, 8.1% with seizure history, whereas in those lacking HS, 7.1% had seizures. As was shown in a larger multicenter cohort previously, 34 this difference was not statistically significant at p < 0.05. HS = hippocampal sclerosis; LATE‐NC = limbic predominant age‐related TDP‐43 encephalopathy neuropathologic change; MRI = magnetic resonance imaging; UK‐ADRC = University of Kentucky Alzheimer's Disease Research Center.…”

“…In older adults, HS is associated with dementia, rather than clinical seizures. 34 Most HS in aging is typically a subset of LATE-NC, as evidenced by the presence of the pathologic features of LATE-NC (TDP-43 pathology) and HS (dramatic cell loss and hippocampal atrophy) in the same individuals. 15,25 There appears to be a progression of hippocampal atrophy across the LATE stages, which in some patients culminate in HS.…”