Cerebral amyloid angiopathy and spontaneous intracerebral haemorrhage. Report of a sporadic case in a young Chinese

Exogenous Aβ seeds induce Aβ depositions in the blood vessels rather than the brain parenchyma, independently of Aβ strain-specific information

Little is known about the effects of parenchymal or vascular amyloid β peptide (Aβ) deposition in the brain. We hypothesized that Aβ strain-specific information defines whether Aβ deposits on the brain parenchyma or blood vessels. We investigated 12 autopsied patients with different severities of Aβ plaques and cerebral amyloid angiopathy (CAA), and performed a seeding study using an Alzheimer’s disease (AD) mouse model in which brain homogenates derived from the autopsied patients were injected intracerebrally. Based on the predominant pathological features, we classified the autopsied patients into four groups: AD, CAA, AD + CAA, and less Aβ. One year after the injection, the pathological and biochemical features of Aβ in the autopsied human brains were not preserved in the human brain extract-injected mice. The CAA counts in the mice injected with all four types of human brain extracts were significantly higher than those in mice injected with PBS. Interestingly, parenchymal and vascular Aβ depositions were observed in the mice that were injected with the human brain homogenate from the less Aβ group. The Aβ and CAA seeding activities, which had significant positive correlations with the Aβ oligomer ratio in the human brain extracts, were significantly higher in the human brain homogenate from the less Aβ group than in the other three groups. These results indicate that exogenous Aβ seeds from different Aβ pathologies induced Aβ deposition in the blood vessels rather than the brain parenchyma without being influenced by Aβ strain-specific information, which might be why CAA is a predominant feature of Aβ pathology in iatrogenic transmission cases. Furthermore, our results suggest that iatrogenic transmission of Aβ pathology might occur due to contamination of brain tissues from patients with little Aβ pathology, and the development of inactivation methods for Aβ seeding activity to prevent iatrogenic transmission is urgently required.

Acquired cerebral amyloid angiopathy: An emerging concept

Cerebral amyloid angiopathy (CAA) is commonly found in older people and in patients with Alzheimer's disease (AD) accompanying cerebrovascular disorders and dementia. Early-onset CAA cases generally have been found only in rare genetic forms of CAA. Interestingly, however, CAA-related hemorrhages have been recently reported in younger people who had histories of neurosurgery with or without evidence of cadaveric dura mater grafts in childhood. It has been established in experimental settings that amyloid β-protein (Aβ) pathology can be transmitted inter-individually with Aβ seeds. Incidental Aβ pathology, predominantly Aβ-CAA, has been recognized in recipients of cadaveric dura mater grafts or cadaveric human growth hormone. These findings suggest that transmission of Aβ seeds through dura mater grafts and other contaminated materials could lead to development of CAA. In addition, neurosurgery or brain injury may contribute to cerebrovascular Aβ deposition through the disturbance of vascular Aβ drainage pathways. Thus, a novel concept, "acquired CAA," has emerged.

The Prevalence and Characterization of Cerebral Microbleeds in Young People Having Intracerebral Hemorrhage

Objective

Cerebral microbleeds (CMBs) are known as the neuroimaging markers of risk in stroke and dementia. Many studies on CMBs in elderly patients with hemorrhagic or ischemic stroke have been reported; however, reports on CMBs in young populations with intracerebral hemorrhage (ICH) are lacking.

Materials and Methods

A total of 272 patients aged 18–54 years presented to our hospital with ICH between December 2009 and August 2017. Among these, CMB presence, count, and topography with respect to ICH were evaluated on magnetic resonance imaging (MRI) gradient echo images (GREs). We also evaluated the prevalence and risk factors of CMBs.

Results

Among 272 patients, only 66 underwent GRE T2-weighted MRI. CMBs were detected in 40 patients (61%), with 29 (73%) being of the multifocal type. Among the 219 CMBs, 150 (68.5%) were of the deep type and 69 (31.5%) of the lobar type. CMB prevalence was higher in men. In multivariate logistic regression analysis, history of hypertension (adjusted odds ratio [aOR], 4.048; 95% confidence interval [CI], 1.14–14.32; p = 0.030), and male sex (aOR, 4.233; 95% CI, 1.09–16.48; p = 0.037) were independently associated with CMBs.

Conclusion

In young patients who presented with spontaneous ICH, CMBs were highly prevalent in 61% of patients and strongly associated with history of hypertension and male sex.

Evidence of amyloid-β cerebral amyloid angiopathy transmission through neurosurgery

Amyloid-β (Aβ) is a peptide deposited in the brain parenchyma in Alzheimer's disease and in cerebral blood vessels, causing cerebral amyloid angiopathy (CAA). Aβ pathology is transmissible experimentally in animals and through medical procedures in humans, such as contaminated growth hormone or dura mater transplantation in the context of iatrogenic prion disease. Here, we present four patients who underwent neurosurgical procedures during childhood or teenage years and presented with intracerebral haemorrhage approximately three decades later, caused by severe CAA. None of these patients carried pathogenic mutations associated with early Aβ pathology development. In addition, we identified in the literature four patients with a history of neurosurgical intervention and subsequent development of CAA. These findings raise the possibility that Aβ pathology may be transmissible, as prion disease is, through neurosurgical procedures.

Cerebral amyloid angiopathy in a young man with a history of traumatic brain injury: a case report and review of the literature

Cerebral amyloid angiopathy (CAA), a cause of recurrent and multiple lobar hemorrhages, characteristically occurs in persons aged ≥55 years. We report a case of a 32-year-old male who had recurrent hemorrhage in the left multiple lobes, with a history of traumatic brain injury and hematoma evacuation at the age of 1 year. He underwent surgical treatment and was histopathologically diagnosed as having CAA. The literature review yielded six CAA cases, including ours, aged less than 55 years. All were male and four had histories of severe TBI, suggesting that male sex and TBI may be associated with CAA in young persons.

High Prevalence of Cerebral Microbleeds in Inner City Young Stroke Patients

BACKGROUND

Data on cerebral microbleeds (CMBs) in younger populations are lacking, particularly in young stroke patients. We sought to characterize CMBs in an inner city cohort of young adults with stroke.

METHODS

CMB presence, count, and topography were assessed on magnetic resonance imaging (MRI) scans of 104 young stroke patients (≤49 years) presenting to Boston Medical Center between January 2006 and February 2010. Subsequent MRIs were assessed for the occurrence of new microbleeds in 29 patients. We performed cross-sectional analysis comparing baseline characteristics between patients with and without microbleeds, and between predefined microbleed burden and topography categories. We performed additional analysis to assess the determinants of new microbleeds on repeat MRI.

RESULTS

Microbleeds were present in 17% of the sample. Male sex (odds ratio [OR] 5.7, 95% confidence interval [CI] 1.0-32.6, P = .049), hypertension (OR 6.2, 95% CI 1.2-32, P = .03), moderate-severe white matter hyperintensities on MRI (OR 5.8, 95% CI 1.6-29.0, P = .01), and intracerebral hemorrhage (ICH; OR 5.0, 95% CI 1.2-20, P = .03) were over-represented in patients with microbleeds. Patients who developed new microbleeds on repeat MRI (14%) had higher microbleed counts on baseline MRI (50% versus 0% ≥ 3 CMBs, P = .02), history of illicit drug use (75% versus 24%, P = .08), positive serum toxicology for cocaine (67% versus 13%, P = .11), ICH as their presenting stroke subtype (50% versus 8%, P = .08), and over-representation of moderate-severe white matter hyperintensities (75% versus 20%, P = .05).

CONCLUSIONS

Results from this inner city cohort suggest that microbleeds are prevalent in young stroke patients and are largely associated with modifiable risk factors.

Cerebral amyloid angiopathy--an underdiagnosed entity in younger adults with lobar intracerebral hemorrhage?

Cerebral amyloid angiopathy (CAA) is a progressive microvascular amyloidosis affecting the small- and medium-sized arterioles and the capillaries of brain parenchyma and leptomeninges, and is recognized as a cause of lobar intracerebral hemorrhage (ICH). We report two patients who experienced recurrent ICH due to CAA at an age of 37 (A) and 42 (B) years, respectively. The classic and modified Boston criteria for the diagnosis of CAA include an age limit of 55 years if no biopsy or postmortem examination is performed; CAA is typically not considered in the differential diagnosis of lobar ICH in younger patients. We assume that sporadic CAA is an underdiagnosed entity in younger adults with lobar ICH.

Cerebral amyloid angiopathy-related hemorrhage. Interaction of APOE epsilon2 with putative clinical risk factors

BACKGROUND AND PURPOSE

Current evidence suggests that the apolipoprotein E (APOE for gene; apoE for protein) epsilon4 allele predisposes to cerebral amyloid angiopathy (CAA) whereas epsilon2 is associated with CAA-related hemorrhage (CAAH). The clinical risk factors for other forms of intracranial hemorrhage are a less-frequent feature of CAAH. In this study we examined potential clinical risk factors in patients with CAAH and assessed these with respect to APOE genotype.

METHODS

Thirty-six patients were identified with a pathological diagnosis of CAAH. Clinical notes were reviewed to document age of hemorrhage onset, history of dementia, antiplatelet/anticoagulant medication, hypertension, minor head trauma, or transient neurological events. In a review of reported cases of CAAH, the frequency of these clinical features was also recorded. APOE genotypes were determined with use of polymerase chain reaction techniques.

RESULTS

There were 24 women and 12 men; the mean age was 70.3 years. One third (n=12) had been taking antiplatelet medication, and a similar number were demented. Nine patients were hypertensive, and 4 had a history of recent minor head trauma. The relative frequency of each of these clinical features was similar to that in previous reports. Forty-four percent (16 of 36) possessed an epsilon2 allele. Antiplatelet or anticoagulant medication, hypertension, or minor head trauma were significantly more frequent antecedents of CAAH in epsilon2 carriers than in non-epsilon2 carriers (81% versus 35%, P=0.008), antiplatelet/anticoagulant medication in particular (P=0.038).

CONCLUSIONS

Our findings suggest that antiplatelet or anticoagulant medication, hypertension, or minor head trauma are most likely to precipitate cerebral hemorrhage in patients with CAA who are also epsilon2 carriers. This may result from isoform-specific effects of apoE on the structure of amyloid-laden blood vessel walls.