Chronic traumatic encephalopathy and athletes.
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ABSTRACT:
SUBMITTER: Meehan W
PROVIDER: S-EPMC4631072 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Chronic traumatic encephalopathy (CTE) is a progressive tauopathy found in contact sport athletes, military veterans, and others exposed to repetitive head injury. Brain white matter atrophy and axonal loss have been reported in CTE but have yet to be well characterized on a molecular or cellular level. Here, we present RNA sequencing profiles of cell nuclei from postmortem dorsolateral frontal white matter from eight individuals with neuropathologically confirmed CTE and eight age- and sex-matched controls. Analyzing these profiles using unbiased clustering approaches, we identified eighteen transcriptomically distinct cell groups (clusters), reflecting cell types and/or cell states, of which a subset showed differences between CTE and control tissue. Independent in situ methods applied on tissue sections adjacent to that used in the single-nucleus RNA-seq work yielded similar findings. Oligodendrocytes were found to be most severely affected in the CTE white matter samples; they appeared diminished in number and altered in the relative proportions across subtype clusters. Further, the CTE-enriched oligodendrocyte population showed greater abundance of transcripts relevant to iron metabolism and cellular stress response. CTE tissue also demonstrated excessive iron accumulation histologically. Astrocyte alterations were more nuanced; total astrocyte number was indistinguishable between CTE and control samples, but transcripts associated with neuroinflammation were elevated in the CTE astrocyte groups as compared to controls. These results demonstrate specific molecular and cellular differences in CTE-associated oligodendrocytes and astrocytes and may provide a starting point for the development of diagnostics and therapeutic interventions.
2021-05-24 | GSE155114 | GEO
Project description:Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative condition associated with repetitive traumatic brain injury (rTBI) seen in contact-sport athletes and military personnel. The medial temporal lobe (MTL; i.e., hippocampus, subiculum, and entorhinal and perirhinal cortices) memory circuit displays tau lesions during the pathological progression of CTE. We examined MTL tissue obtained from 40 male Caucasian and African American athletes who received a postmortem CTE neuropathological diagnosis defined as stage II, III, or IV. Sections were immunolabeled using an early (AT8) or a late (TauC3) marker for pathological tau and for amyloid beta (Aβ) species (6E10, Aβ1-42 and thioflavin S). Stereological analysis revealed that stage III had significantly less AT8-positive neurons and dystrophic neurites than stage IV in all MTL regions except hippocampal subfield CA3, whereas significantly more AT8-positive neurons, dystrophic neurites, and neurite clusters were found in the perirhinal cortex, entorhinal cortex, hippocampal CA1, and subiculum of CTE stage III compared with stage II. TauC3-positive pathology was significantly higher in the perirhinal and subicular cortex of stage IV compared to stage III and the perirhinal cortex of stage III compared to stage II. AT8-positive neurite clusters were observed in stages III and IV, but virtually absent in stage II. When observed, Aβ pathology appeared as amyloid precursor protein (APP)/Aβ (6E10)-positive diffuse plaques independent of region. Thioflavine S labeling, did not reveal evidence for fibril or neuritic pathology associated with plaques, confirming a diffuse, non-cored plaque phenotype in CTE. Total number of AT8-positive profiles correlated with age at death, age at symptom onset, and time from retirement to death. There was no association between AT8-positive tau pathology and age sport began, years played, or retirement age, and no difference between CTE stage and the highest level of sport played. In summary, our findings demonstrate different tau profiles in the MTL across CTE stages, proffering CA3 tau pathology and MTL dystrophic neurite clusters as possible markers for the transition between early (II) and late (III/IV) stages, while highlighting CTE as a progressive noncommunicative tauopathy.
| S-EPMC6909582 | biostudies-literature
Project description:Repetitive traumatic brain injury (rTBI) is one of the major risk factors for the abnormal deposition of phosphorylated tau (PT) in the brain and chronic traumatic encephalopathy (CTE). CTE and temporal lobe epilepsy (TLE) affect the limbic system, but no comparative studies on PT distribution in TLE and CTE are available. It is also unclear whether PT pathology results from repeated head hits (rTBI). These gaps prevent a thorough understanding of the pathogenesis and clinical significance of PT, limiting our ability to develop preventative and therapeutic interventions. We quantified PT in TLE and CTE to unveil whether a history of rTBI is a prerequisite for PT accumulation in the brain. Six postmortem CTE (mean 73.3 years) and age matched control samples were compared to 19 surgically resected TLE brain specimens (4 months-58 years; mean 27.6 years). No history of TBI was present in TLE or control; all CTE patients had a history of rTBI. TLE and CTE brain displayed increased levels of PT as revealed by immunohistochemistry. No age-dependent changes were noted, as PT was present as early as 4 months after birth. In TLE and CTE, cortical neurons, perivascular regions around penetrating pial vessels and meninges were immunopositive for PT; white matter tracts also displayed robust expression of extracellular PT organized in bundles parallel to venules. Microscopically, there were extensive tau-immunoreactive neuronal, astrocytic and degenerating neurites throughout the brain. In CTE perivascular tangles were most prominent. Overall, significant differences in staining intensities were found between CTE and control (P<0.01) but not between CTE and TLE (P=0.08). pS199 tau analysis showed that CTE had the most high molecular weight tangle-associated tau, whereas epileptic brain contained low molecular weight tau. Tau deposition may not be specific to rTBI since TLE recapitulated most of the pathological features of CTE.
| S-EPMC4853900 | biostudies-literature
Project description:ObjectiveThe goal of this study was to examine the clinical presentation of chronic traumatic encephalopathy (CTE) in neuropathologically confirmed cases.MethodsThirty-six adult male subjects were selected from all cases of neuropathologically confirmed CTE at the Boston University Center for the Study of Traumatic Encephalopathy brain bank. Subjects were all athletes, had no comorbid neurodegenerative or motor neuron disease, and had next-of-kin informants to provide retrospective reports of the subjects' histories and clinical presentations. These interviews were conducted blind to the subjects' neuropathologic findings.ResultsA triad of cognitive, behavioral, and mood impairments was common overall, with cognitive deficits reported for almost all subjects. Three subjects were asymptomatic at the time of death. Consistent with earlier case reports of boxers, 2 relatively distinct clinical presentations emerged, with one group whose initial features developed at a younger age and involved behavioral and/or mood disturbance (n = 22), and another group whose initial presentation developed at an older age and involved cognitive impairment (n = 11).ConclusionsThis suggests there are 2 major clinical presentations of CTE, one a behavior/mood variant and the other a cognitive variant.
| S-EPMC3795597 | biostudies-literature
Project description:Proteomic sequencing of postmortem human brain can identify dysfunctional proteins that contribute to neurodegenerative disorders like Alzheimer’s disease and frontotemporal dementia. Similar studies in chronic traumatic encephalopathy are limited, but may provide important new insights into this disorder. Given our previous success with identifying pathology associated proteins, we performed proteomic sequencing of detergent insoluble brain homogenates from frontal cortex of deceased subjects with CTE covering a range of CTE pathologic stages. We compared the insoluble proteome of CTE brain to control and AD brains to identify differentially expressed proteins. We identified over 4000 proteins in CTE brains, including significant enrichment of the microtubule associated protein tau. We also found enrichment and pathologic aggregation of RNA processing factors as seen previously in AD, supporting the previously recognized overlap between AD and CTE. In addition to these similarities, we identified CTE-specific enrichment of a number of proteins which increase with increasing severity of CTE pathology. NADPH dehydrogenase quinone 1 (NQO1) was one of the proteins which showed significant enrichment in CTE and also correlated with increasing CTE stage. NQO1 demonstrated neuropathologic correlation with hyperphosphorylated tau in glial cells, mainly astrocytes. These results demonstrate that quantitative proteomic sequencing of CTE postmortem human brain can identify disease relevant findings and novel cellular pathways involved in CTE pathogenesis.
2017-11-27 | PXD007694 | Pride
Project description:The genetic basis of chronic traumatic encephalopathy (CTE) is poorly understood. Variation in transmembrane protein 106B (TMEM106B) has been associated with enhanced neuroinflammation during aging and with TDP-43-related neurodegenerative disease, and rs3173615, a missense coding SNP in TMEM106B, has been implicated as a functional variant in these processes. Neuroinflammation and TDP-43 pathology are prominent features in CTE. The purpose of this study was to determine whether genetic variation in TMEM106B is associated with CTE risk, pathological features, and ante-mortem dementia. Eighty-six deceased male athletes with a history of participation in American football, informant-reported Caucasian, and a positive postmortem diagnosis of CTE without comorbid neurodegenerative disease were genotyped for rs3173615. The minor allele frequency (MAF?=?0.42) in participants with CTE did not differ from previously reported neurologically normal controls (MAF?=?0.43). However, in a case-only analysis among CTE cases, the minor allele was associated with reduced phosphorylated tau (ptau) pathology in the dorsolateral frontal cortex (DLFC) (AT8 density, odds ratio [OR] of increasing one quartile?=?0.42, 95% confidence interval [CI] 0.22-0.79, p?=?0.008), reduced neuroinflammation in the DLFC (CD68 density, OR of increasing one quartile?=?0.53, 95% CI 0.29-0.98, p?=?0.043), and increased synaptic protein density (??=?0.306, 95% CI 0.065-0.546, p?=?0.014). Among CTE cases, TMEM106B minor allele was also associated with reduced ante-mortem dementia (OR?=?0.40, 95% CI 0.16-0.99, p?=?0.048), but was not associated with TDP-43 pathology. All case-only models were adjusted for age at death and duration of football play. Taken together, variation in TMEM106B may have a protective effect on CTE-related outcomes.
| S-EPMC6215686 | biostudies-literature
Project description:Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with repetitive mild traumatic brain injury. It is defined pathologically by the abnormal accumulation of tau in a unique pattern that is distinct from other tauopathies, including Alzheimer's disease (AD). Although trauma has been suggested to increase amyloid ? peptide (A?) levels, the extent of A? deposition in CTE has not been thoroughly characterized. We studied a heterogeneous cohort of deceased athletes and military veterans with neuropathologically diagnosed CTE (n = 114, mean age at death = 60) to test the hypothesis that A? deposition is altered in CTE and associated with more severe pathology and worse clinical outcomes. We found that A? deposition, either as diffuse or neuritic plaques, was present in 52 % of CTE subjects. Moreover, A? deposition in CTE occurred at an accelerated rate and with altered dynamics in CTE compared to a normal aging population (OR = 3.8, p < 0.001). We also found a clear pathological and clinical dichotomy between those CTE cases with A? plaques and those without. A? deposition was significantly associated with the presence of the APOE ?4 allele (p = 0.035), older age at symptom onset (p < 0.001), and older age at death (p < 0.001). In addition, when controlling for age, neuritic plaques were significantly associated with increased CTE tauopathy stage (? = 2.43, p = 0.018), co-morbid Lewy body disease (OR = 5.01, p = 0.009), and dementia (OR = 4.45, p = 0.012). A subset of subjects met the diagnostic criteria for both CTE and AD, and in these subjects both A? plaques and total levels of A?1-40 were increased at the depths of the cortical sulcus compared to the gyral crests. Overall, these findings suggest that A? deposition is altered and accelerated in a cohort of CTE subjects compared to normal aging and that A? is associated with both pathological and clinical progression of CTE independent of age.
| S-EPMC4529056 | biostudies-literature
Project description:It has long been suggested that prior traumatic brain injury (TBI) increases the subsequent incidence of chronic neurodegenerative disorders, including Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis. Among these, the association with Alzheimer disease has the strongest support. There is also a long-recognized association between repeated concussive insults and progressive cognitive decline or other neuropsychiatric abnormalities. The latter was first described in boxers as dementia pugilistica, and has received widespread recent attention in contact sports such as professional American football. The term chronic traumatic encephalopathy was coined to attempt to define a "specific" entity marked by neurobehavioral changes and the extensive deposition of phosphorylated tau protein. Nearly lost in the discussions of post-traumatic neurodegeneration after traumatic brain injury has been the role of sustained neuroinflammation, even though this association has been well established pathologically since the 1950s, and is strongly supported by subsequent preclinical and clinical studies. Manifested by extensive microglial and astroglial activation, such chronic traumatic brain inflammation may be the most important cause of post-traumatic neurodegeneration in terms of prevalence. Critically, emerging preclinical studies indicate that persistent neuroinflammation and associated neurodegeneration may be treatable long after the initiating insult(s).
| S-EPMC4322076 | biostudies-literature
Project description:Traumatic brain injury (TBI) is one of the main causes of death worldwide. It is a complex injury that influences cellular physiology, causes neuronal cell death, and affects molecular pathways in the brain. This in turn can result in sensory, motor, and behavioral alterations that deeply impact the quality of life. Repetitive mild TBI can progress into chronic traumatic encephalopathy (CTE), a neurodegenerative condition linked to severe behavioral changes. While current animal models of TBI and CTE such as rodents, are useful to explore affected pathways, clinical findings therein have rarely translated into clinical applications, possibly because of the many morphofunctional differences between the model animals and humans. It is therefore important to complement these studies with alternative animal models that may better replicate the individuality of human TBI. Comparative studies in animals with naturally evolved brain protection such as bighorn sheep, woodpeckers, and whales, may provide preventive applications in humans. The advantages of an in-depth study of these unconventional animals are threefold. First, to increase knowledge of the often-understudied species in question; second, to improve common animal models based on the study of their extreme counterparts; and finally, to tap into a source of biological inspiration for comparative studies and translational applications in humans.
| S-EPMC8596618 | biostudies-literature
Project description:Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disorder associated with repetitive traumatic brain injury. Multiple system atrophy (MSA) is a Parkinsonian disorder that can result in repetitive falls with associated head trauma. We hypothesized that patients with neurodegenerative disorders like MSA could develop CTE pathology. Therefore, we assessed CTE pathology in 139 MSA cases in our brain bank. Sections from convexity cerebral cortices were screened by immunohistochemistry with anti-phospho-tau antibody. For cases with suggestive CTE pathology, further sections of basal forebrain and hippocampus were immunostained. Consensus criteria were used to make the diagnosis of CTE and aging-related tau astrogliopathy (ARTAG) was differentiated from CTE pathology. Pertinent clinical information was derived from the available records and online searches. Of the 139 MSA cases, 8 (6%) had CTE pathology and 10 (8%) had ARTAG pathology. All 8 cases with CTE were male and 4 of them had a documented history of contact sports. The median age at death in MSA with CTE was younger than in MSA without CTE or MSA with ARTAG (60, 67, and 74 years, respectively; p?=?0.002). Even without a known history of contact sports or head trauma, a small subset of cases with MSA had CTE pathology.
| S-EPMC5029441 | biostudies-literature