Clinical considerations in early-onset cerebral amyloid angiopathy

Deciphering the role of APOE in cerebral amyloid angiopathy: from genetic insights to therapeutic horizons

Cerebral amyloid angiopathy (CAA), characterized by the deposition of amyloid-β (Aβ) peptides in the walls of medium and small vessels of the brain and leptomeninges, is a major cause of lobar hemorrhage in elderly individuals. Among the genetic risk factors for CAA that continue to be recognized, the apolipoprotein E (APOE) gene is the most significant and prevalent, as its variants have been implicated in more than half of all patients with CAA. While the presence of the APOE ε4 allele markedly increases the risk of CAA, the ε2 allele confers a protective effect relative to the common ε3 allele. These allelic variants encode three APOE isoforms that differ at two amino acid positions. The primary physiological role of APOE is to mediate lipid transport in the brain and periphery; however, it has also been shown to be involved in a wide array of biological functions, particularly those involving Aβ, in which it plays a known role in processing, production, aggregation, and clearance. The challenges posed by the reliance on postmortem histological analyses and the current absence of an effective intervention underscore the urgency for innovative APOE-targeted strategies for diagnosing CAA. This review not only deepens our understanding of the impact of APOE on the pathogenesis of CAA but can also help guide the exploration of targeted therapies, inspiring further research into the therapeutic potential of APOE.

Gustav Oppenheim (1882-1937) and the Discovery of Cerebral Amyloid Angiopathy

The discovery of cerebral amyloid angiopathy (CAA) is frequently attributed to Dr. Gustav Oppenheim-a man who has been largely passed over in history. Oppenheim's clinical and neuropathologic research covered a variety of disorders, but his name is best known for his work on senile dementia and CAA. Although Oppenheim was in fact not the first to discover CAA, his neuropathologic observations and inferences on neurodegenerative disease proved to be remarkably faithful to our modern understanding of neurodegenerative diseases. As a neurologist, he served in the First World War and was later subjected to religious persecutions in the leadup to the Holocaust but was not fortunate enough to emigrate before his death. The life, social impact, and previously overlooked contributions to science and medicine by Oppenheim are detailed.

Cerebral Amyloid Angiopathy-Related Inflammation in Iatrogenic Cerebral Amyloid Angiopathy

INTRODUCTION

Cerebral amyloid angiopathy (CAA) related inflammation (CAA-ri) is considered to be a distinct syndrome caused by an inflammatory response to amyloid-β deposition in the walls of small leptomeningeal and cortical vessels in patients with sporadic CAA. However, recent data suggest that inflammation might contribute to a broader range of CAA subtypes.

RESULTS

We describe a case of probable iatrogenic CAA (iCAA), which manifested with multiple intracerebral haemorrhages complicated by the development of clinical and radiological features of CAA-ri, which responded to steroids. Clinical, neuroimaging and CSF data suggested possible co-existing Alzheimer's pathology.

DISCUSSION

CAA-ri may occur in association with iCAA, suggesting that a broader spectrum of patients might benefit from steroid treatment than previously assumed.

Vascular and glymphatic dysfunction as drivers of cognitive impairment in Alzheimer's disease: Insights from computational approaches

Alzheimer's disease (AD) is driven by complex interactions between vascular dysfunction, glymphatic system impairment, and neuroinflammation. Vascular aging, characterized by arterial stiffness and reduced cerebral blood flow (CBF), disrupts the pulsatile forces necessary for glymphatic clearance, exacerbating amyloid-beta (Aβ) accumulation and cognitive decline. This review synthesizes insights into the mechanistic crosstalk between these systems and explores their contributions to AD pathogenesis. Emerging machine learning (ML) tools, such as DeepLabCut and Motion sequencing (MoSeq), offer innovative solutions for analyzing multimodal data and enhancing diagnostic precision. Integrating ML with imaging and behavioral analyses bridges gaps in understanding vascular-glymphatic dysfunction. Future research must prioritize these interactions to develop early diagnostics and targeted interventions, advancing our understanding of neurovascular health in AD.

Genetic testing in dementia

There is growing public awareness and concern regarding dementia risk. In addition, genetic testing is increasingly accessible and is at the point of being integrated into routine clinical practice. As a result, there is a pressing need for treating clinicians to have the appropriate knowledge base to request and consent for diagnostic genetic testing in cognitive clinics. We outline our approach to genetic testing in patients with Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies and vascular cognitive impairment. We discuss when to consider testing, the consenting process, and the interpretation and communication of genetic test results.

Clinical Reasoning: A 32-Year-Old Woman With Recurrent Intracerebral Hemorrhages

Evaluating patients with intracerebral hemorrhage is common practice in the field of stroke neurology but can be complicated and may require extensive evaluation in younger patients with no history of hypertension. In this case, a healthy 32-year-old woman presented with an acute spontaneous lobar intracerebral hemorrhage. Neurologic workup required extensive imaging evaluation, genetic testing, and a thorough evaluation of patient and family medical history to identify the final diagnosis. This case highlights the diagnostic approach and importance of thorough clinical evaluation of young patients with intracerebral hemorrhages. Readers will walk through the stepwise diagnostic approach to arrive at the leading diagnosis with a review of the possible differential diagnoses and a discussion of this rare condition.

CSF and plasma biomarkers in cerebral amyloid angiopathy: A single-center study and a systematic review/meta-analysis

INTRODUCTION

There are limited data regarding cerebrospinal fluid (CSF) and plasma biomarkers among patients with Cerebral Amyloid Angiopathy (CAA). We sought to investigate the levels of four biomarkers [β-amyloids (Aβ42 and Aβ40), total tau (tau) and phosphorylated tau (p-tau)] in CAA patients compared to healthy controls (HC) and patients with Alzheimer Disease (AD).

PATIENTS AND METHODS

A systematic review and meta-analysis of published studies, including also a 5 year single-center cohort study, with available data on CSF and plasma biomarkers in symptomatic sporadic CAA versus HC and AD was conducted. Biomarkers' comparisons were investigated using random-effects models based on the ratio of mean (RoM) biomarker concentrations. RoM < 1 and RoM > 1 indicate lower and higher biomarker concentration in CAA compared to another population, respectively.

RESULTS

We identified nine cohorts, comprising 327 CAA patients (mean age: 71 ± 5 years; women: 45%) versus 336 HC (mean age: 65 ± 5 years; women: 45%) and 384 AD patients (mean age: 68 ± 3 years; women: 53%) with available data on CSF biomarkers. CSF Aβ42 levels [RoM: 0.47; 95% CI: 0.36-0.62; p < 0.0001], Aβ40 levels [RoM: 0.70; 95% CI: 0.63-0.79; p < 0.0001] and the ratio Aβ42/Aβ40 [RoM: 0.62; 95% CI: 0.39-0.98; p = 0.0438] differentiated CAA from HC. CSF Aβ40 levels [RoM: 0.73; 95% CI: 0.64-0.83; p = 0.0003] differentiated CAA from AD. CSF tau and p-tau levels differentiated CAA from HC [RoM: 1.71; 95% CI: 1.41-2.09; p = 0.0002 and RoM: 1.44; 95% CI: 1.20-1.73; p = 0.0014, respectively] and from AD [RoM: 0.65; 95% CI: 0.58-0.72; p < 0.0001 and RoM: 0.64; 95% CI: 0.57-0.71; p < 0.0001, respectively]. Plasma Aβ42 [RoM: 1.14; 95% CI: 0.89-1.45; p = 0.2079] and Aβ40 [RoM: 1.07; 95% CI: 0.91-1.25; p = 0.3306] levels were comparable between CAA and HC.

CONCLUSIONS

CAA is characterized by a distinct CSF biomarker pattern compared to HC and AD. CSF Aβ40 levels are lower in CAA compared to HC and AD, while tau and p-tau levels are higher in CAA compared to HC, but lower in comparison to AD patients.

GGC repeat expansions in NOTCH2NLC cause uN2CpolyG cerebral amyloid angiopathy

The expansion of GGC repeats within NOTCH2NLC leads to translation of the uN2CpolyG protein, the primary pathogenic factor in neuronal intranuclear inclusion disease (NIID). The aim of this study was to explore the deposition of uN2CpolyG as an amyloid in the vessel wall, leading to uN2CpolyG cerebral amyloid angiopathy-related cerebral microbleeds (CMBs). A total of 97 patients with genetically confirmed NIID were enrolled in this study. We analysed the presence of CMBs using susceptibility-weighted imaging sequences and compared general clinical information, cerebrovascular risk factors, stroke history, antiplatelet medication use and MRI features between NIID patients with and without CMBs. We also performed haematoxylin and eosin, Perl's, Congo red and Thioflavin S staining, ubiquitin, p62 and uN2CpolyG immunostaining on brain tissue obtained from four NIID patients. A total of 354 CMBs were detected among 41 patients with NIID, with nearly half located in the deep brain, one-third in the lobes and ∼20% in the infratentorial area. No significant differences in cerebrovascular disease risk factors or history of antiplatelet drug use were observed between patients with and without CMBs. However, patients with CMBs had suffered a higher incidence of previous ischaemic and haemorrhagic stroke events. This group also had a higher incidence of recent subcortical infarcts and a higher proportion of white matter lesions in the external capsule and temporal pole. Conversely, patients without CMBs showed higher detection of high signals at the corticomedullary junction on diffusion-weighted imaging and more pronounced brain atrophy. Haematoxylin and eosin staining showed blood vessel leakage and haemosiderin-laden macrophage clusters, and Prussian blue staining revealed iron deposition in brain tissue. CMBs occurred more frequently in small vessels lacking intranuclear inclusions, and extensive degeneration of endothelial cells and smooth muscle fibres was observed mainly in vessels lacking inclusions. Congo red-positive amyloid deposition was observed in the cerebral vessels of NIID patients, with disordered filamentous fibres appearing under an electron microscope. Additionally, the co-localization of Thioflavin S-labelled amyloid and uN2CpolyG protein in the cerebral vascular walls of NIID patients further suggested that uN2CpolyG is the main pathogenic protein in this form of amyloid angiopathy. In conclusion, we reviewed patients with GGC repeat expansion of NOTCH2NLC from a new perspective, providing initial clinical, neuroimaging and pathological evidence suggesting that uN2CpolyG might contribute to a distinct type of cerebral amyloid angiopathy.

An older man with progressive short-term memory loss and confusion

ABSTRACT

A 72-year-old man with progressive memory loss and confusion presented to a neurology clinic for evaluation. He initially had difficulty remembering names and misplaced objects; however, his memory deficits had progressed, and more recently he had numerous car accidents and difficulty managing his own medications and finances. Cognitive testing revealed significant memory deficits reflecting moderate-stage dementia, and his brain MRI showed several cortical microbleeds and an area of siderosis consistent with the diagnosis of cerebral amyloid angiopathy (CAA). This case report provides an overview of a classic case of CAA and its potential treatment options.

Iatrogenic cerebral amyloid angiopathy: Two case reports to explore clinical heterogeneity and pathological patterns

INTRODUCTION

These case reports illustrate Iatrogenic Cerebral Amyloid Angiopathy (iCAA) due to neurosurgical procedures. Recent studies propose prion transmission during neurosurgery as a potential mechanism for β-amyloid seed implantation, linking neurosurgical history to the development of iCAA. The majority of reported cases in the literature have an unfavorable prognosis, with recurrence of intracerebral hemorrahge (ICH) and subsequent death during the first months of follow-up. There is no effective treatment for preventing the progression of the disease.

RESULTS

a 41-year-old man with a previous history of left frontotemporal traumatic brain injury and subsequent neurosurgical intervention in childhood was admitted with an ICH leading to the diagnosis of iCAA. The patient's history of exposure, combined with imaging studies and neuropsychological assessments, supported the suspicion of iCAA. Confirmatory PET-CT scans revealed β-amyloid deposits in the cortical regions, aligning with the proposed criteria for iCAA. At the 2-year follow-up, the patient presents an NIHSS of 0 and a Modified Rankin Scale (mRS) of 1. The second case involved a 50-year-old man with a history of surgical treatment for Arnold-Chiari malformation, who developed transient neurological deficits and presented multiple ICH. The patient's history of neurosurgical intervention and the radiological and clinical features supported the diagnosis of probable iAAC. Despite a negative PET-CT result, CSF analysis provided evidence of ß-amyloid accumulation in the CNS. At the 6-year follow-up, the patient presented an NIHSS of 1(hemihypoesthesia) and mRS of 3.

CONCLUSION

iCAA is an emerging pathology probably driven by prion transmission of β-amyloid seed after neurosurgical interventions. It is important to suspect this condition in young patients with ICH and a history of neurosurgical procedure. Recognizing iCAA's clinical and radiological features is crucial for early identification. The diagnosis process is based on demonstrating the accumulation of β-amyloid protein in the central nervous system using PET-CT or cerebrospinal fluid (CSF) studies and also conducting genetics studies. As an evolving pathology without a clear pathophysiology and a potential divergent evolution between phenotypes, establishing standardized diagnostic criteria and a multicenter registry is imperative for a comprehensive understanding of iCAA.

Intracerebral haemorrhage - mechanisms, diagnosis and prospects for treatment and prevention

Intracerebral haemorrhage (ICH) is a devastating condition associated with high mortality and substantial residual disability among survivors. Effective treatments for the acute stages of ICH are limited. However, promising findings from randomized trials of therapeutic strategies, including acute care bundles that target anticoagulation therapies, blood pressure control and other physiological parameters, and trials of minimally invasive neurosurgical procedures have led to renewed optimism that patient outcomes can be improved. Currently ongoing areas of research for acute treatment include anti-inflammatory and haemostatic treatments. The implementation of effective secondary prevention strategies requires an understanding of the aetiology of ICH, which involves vascular and brain parenchymal imaging; the use of neuroimaging markers of cerebral small vessel disease improves classification with prognostic relevance. Other data underline the importance of preventing not only recurrent ICH but also ischaemic stroke and cardiovascular events in survivors of ICH. Ongoing and planned randomized controlled trials will assess the efficacy of prevention strategies, including antiplatelet agents, oral anticoagulants or left atrial appendage occlusion (in patients with concomitant atrial fibrillation), and optimal management of long-term blood pressure and statin use. Together, these advances herald a new era of improved understanding and effective interventions to reduce the burden of ICH.

Neuroradiological Findings in Cerebral Amyloid Angiopathy with a Particular Consideration of the Boston Criteria 2.0: An Imaging Review

In the elderly, cerebral amyloid angiopathy (CAA) is the most common cause for intracranial lobar hemorrhages. CAA is caused by the accumulation of amyloid-β fibrils in cortical and leptomeningeal vessels. In 2022, the Boston Criteria 2.0 became the new diagnostic standard for CAA, following the Modified Boston Criteria of 2010. The diagnostic criteria are a composite of clinical, imaging and histopathological findings. In the latest version of the Boston Criteria, neuroradiological imaging findings were even expanded compared to the previous version. Crucially, the correct application of the diagnostic criteria is necessary to avoid over- and underdiagnosis. The aim of this review is to demonstrate the diagnostic criteria for CAA with an emphasis on typical imaging findings which are part of the Boston Criteria 2.0 and other imaging findings suggestive of CAA.

Beta-Amyloid Related Neurodegenerative and Neurovascular Diseases: Potential Implications for Transfusion Medicine

Cerebral amyloid angiopathy (CAA) is a progressive cerebrovascular and neurodegenerative disorder that is caused by the aberrant accumulation of soluble beta-amyloid isoforms in the small vessel walls of the cerebral and cerebellar cortices and the leptomeninges. Vascular beta-amyloid deposition increases vulnerability to intracerebral hemorrhage (ICH). Clinically, CAA can be the underlying cause of up to half of spontaneous lobar ICHs and can also present with convexity subarachnoid hemorrhage, transient focal neurologic episodes and progressive cognitive decline leading to dementia. The majority of CAA is sporadic, with increasing prevalence with age and often coexists with Alzheimer's Disease (AD). Genetic and iatrogenic etiologies are rare. Cases of CAA and AD have been linked to the use of cadaveric pituitary hormone and later life iatrogenic CAA has also been described following early-life neurosurgical procedures with cadaveric dura grafts. Together these data suggest a capacity of beta-amyloid transmissibility. A recent study found that in over 1 million transfusion recipients from donors who later developed (i) >1 ICH or (ii) one ICH event and dementia, had an elevated risk of developing future ICH. Considering prior reports of transfusion associated variant-Creutzfeldt Jakob Disease in humans and in vivo evidence in sheep, coupled with emerging data supporting beta-amyloid's prion-like properties, raises the question of whether CAA could be transmissible by blood transfusion. This would also have implications for screening, especially in an era of emerging plasma biomarkers of cerebral amyloidosis. Given the public health concerns raised by this biologically plausible question, there is a need for future studies with well-characterized definitions - and temporal ascertainment - of CAA exposure and outcomes to examine whether CAA is transfusion-transmissible, and, if so, with what frequency and timing of onset.

PSEN2 Mutations May Mimic Frontotemporal Dementia: Two New Case Reports and a Review

BACKGROUND

Monogenic Alzheimer's disease (AD) has severe health and socioeconomic repercussions. Its rarest cause is presenilin 2 (PSEN2) gene mutations. We present two new cases with presumed PSEN2-AD with unusual clinical and neuroimaging findings in order to provide more information on the pathophysiology and semiology of these patients.

METHODS

Women aged 69 and 62 years at clinical onset, marked by prominent behavioral and language dysfunction, progressing to severe dementia within three years were included. The complete study is depicted. In addition, a systematic review of the PSEN2-AD was performed.

RESULTS

Neuroimaging revealed pronounced frontal white matter hyperintensities (WMH) and frontotemporal atrophy/hypometabolism. The genetic study unveiled PSEN2 variants: c.772G>A (p.Ala258Thr) and c.1073-2_1073-1del. Both cerebrospinal fluid (CSF) and experimental blood biomarkers shouldered AD etiology.

CONCLUSIONS

Prominent behavioral and language dysfunction suggesting frontotemporal dementia (FTD) may be underestimated in the literature as a clinical picture in PSEN2 mutations. Thus, it may be reasonable to include PSEN2 in genetic panels when suspecting FTDL. PSEN2 mutations may cause striking WMH, arguably related to myelin disruption induced by amyloid accumulation.

Genetic Determinants of Vascular Dementia

Vascular dementia (VaD) is a prevalent form of cognitive impairment with underlying vascular etiology. In this review, we examine recent genetic advancements in our understanding of VaD, encompassing a range of methodologies including genome-wide association studies, polygenic risk scores, heritability estimates, and family studies for monogenic disorders revealing the complex and heterogeneous nature of the disease. We report well known genetic associations and highlight potential pathways and mechanisms implicated in VaD and its pathological risk factors, including stroke, cerebral small vessel disease, and cerebral amyloid angiopathy. Moreover, we discuss important modifiable risk factors such as hypertension, diabetes, and dyslipidemia, emphasizing the importance of a multifactorial approach in prevention, treatment, and understanding the genetic basis of VaD. Last, we outline several areas of scientific advancements to improve clinical care, highlighting that large-scale collaborative efforts, together with an integromics approach can enhance the robustness of genetic discoveries. Indeed, understanding the genetics of VaD and its pathophysiological risk factors hold the potential to redefine VaD on the basis of molecular mechanisms and to generate novel diagnostic, prognostic, and therapeutic tools.

Parental Influence on Intracerebral Hemorrhage Onset in Hereditary Dutch-Type Cerebral Amyloid Angiopathy

INTRODUCTION

Dutch-type cerebral amyloid angiopathy (D-CAA) is an autosomal dominant hereditary form of CAA causing intracerebral hemorrhage (ICH) and cognitive decline. The age of onset of ICH in D-CAA mutation carriers is strikingly variable and ranges from late thirties up to 70 years. We investigated the presence of genetic anticipation and assessed the influence of parental age at onset and sex on age of ICH onset in offspring.

METHODS

We included (potential) D-CAA mutation carriers from our prospective D-CAA family database. Participants were sent a questionnaire by mail and asked for the onset age of symptomatic ICH and the onset age of symptomatic ICH of their affected first-degree relative(s), their siblings and affected parent. We used a Cox regression model with the age of onset of the parent as the covariate and the sex of the offspring as the factor. Next, we replaced the sex of the offspring with a factor with four levels: mother/daughter, mother/son, father/daughter, and father/son. We used a random effect per household.

RESULTS

A total of 66 respondents completed the questionnaire. Reported mean age of first symptomatic ICH was similar (both 52 years, p = 0.87) for D-CAA parents (n = 60) and their offspring (n = 100). Offspring with a mother with D-CAA seemed to have an earlier ICH onset (50 years, standard deviation [SD] ± 7) than offspring with a paternal inheritance (54 years, SD ± 6, p = 0.03). There was no association between onset of first ICH of the parent and offspring after adding sex of the offspring to the Cox regression model: hazard ratio 0.99, 95% CI: 0.94-1.03, p = 0.51. The interaction between parent's sex and child's sex was not significant (p = 0.70). The results with and without random effect were essentially identical.

CONCLUSION

We found no indication for genetic anticipation in D-CAA in general, although maternal inheritance seemed to be associated with an earlier ICH onset.

Exploratory Mass Spectrometry of Cerebrospinal Fluid from Persons with Autopsy-Confirmed LATE-NC

Common neuropathologies associated with dementia include Alzheimer's disease neuropathologic change (ADNC) and limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC). Biofluid proteomics provides a window into the pathobiology of dementia and the information from biofluid tests may help guide clinical management. Participants (n = 29) had been autopsied and had antemortem CSF draws in a longitudinal cohort of older adults at the University of Kentucky AD Research Center. Cases were designated as LATE-NC + if they had LATE-NC stage > 1 (n = 9); the remaining 20 cases were designated LATE-NC-. This convenience sample of CSF specimens was analyzed in two separate processes: From one group, aliquots were depleted of highly abundant proteins using affinity spin columns. Tryptic digests of sample proteins were subjected to liquid chromatographic separation and mass spectrometry. Relative quantification was performed using Sciex software. Peptides referent to a total of 949 proteins were identified in the samples depleted of abundant proteins, and 820 different proteins were identified in the non-depleted samples. When the Bonferroni/false-discovery statistical correction was applied to account for having made multiple comparison tests, only 4 proteins showed differential expression (LATE-NC + vs LATE-NC-) in the non-depleted samples (RBP4, MIF, IGHG3, and ITM2B). Post hoc western blots confirmed that RBP4 expression was higher in the LATE-NC + cases at the group level. In summary, an exploratory assessment of proteomes of autopsy-confirmed LATE-NC and non-LATE-NC CSF did not demonstrate a clear-cut proteomic fingerprint that distinguished the two groups. There was, however, an increase in RBP4 protein levels in CSF from LATE-NC cases.

The presenilin 1 mutation P436S causes familial Alzheimer's disease with elevated Aβ43 and atypical clinical manifestations

INTRODUCTION

Familial Alzheimer's disease (fAD) is heterogeneous in terms of age at onset and clinical presentation. A greater understanding of the pathogenicity of fAD variants and how these contribute to heterogeneity will enhance our understanding of the mechanisms of AD more widely.

METHODS

To determine the pathogenicity of the unclassified PSEN1 P436S mutation, we studied an expanded kindred of eight affected individuals, with magnetic resonance imaging (MRI) (two individuals), patient-derived induced pluripotent stem cell (iPSC) models (two donors), and post-mortem histology (one donor).

RESULTS

An autosomal dominant pattern of inheritance of fAD was seen, with an average age at symptom onset of 46 years and atypical features. iPSC models and post-mortem tissue supported high production of amyloid beta 43 (Aβ43). PSEN1 peptide maturation was unimpaired.

DISCUSSION

We confirm that the P436S mutation in PSEN1 causes atypical fAD. The location of the mutation in the critical PSEN1 proline-alanine-leucine-proline (PALP) motif may explain the early age at onset despite appropriate protein maturation.

HIGHLIGHTS

PSEN1 P436S mutations cause familial Alzheimer's disease. This mutation is associated with atypical clinical presentation. Induced pluripotent stem cells (iPSCs) and post-mortem studies support increased amyloid beta (Aβ43) production. Early age at onset highlights the importance of the PALP motif in PSEN1 function.

Iatrogenic cerebral amyloid angiopathy in older adults

BACKGROUND AND PURPOSE

An increasing number of cases of iatrogenic cerebral amyloid angiopathy (CAA) have now been reported worldwide. Proposed diagnostic criteria require a history of medical intervention with potential for amyloid-β transmission, for example those using cadaveric dura mater or requiring instrumentation of the brain or spinal cord. Clinical presentation occurs after an appropriate latency (usually three or four decades); to date, most patients with iatrogenic CAA have had 'early-onset' disease (compared to sporadic, age-related, CAA), as a consequence of childhood procedures.

RESULTS

We describe five cases of possible iatrogenic CAA in adults presenting in later life (aged 65 years and older); all had prior neurosurgical interventions and presented after a latency suggestive of iatrogenic disease (range 30-39 years). Use of cadaveric dura mater was confirmed in one case, and highly likely in the remainder.

CONCLUSION

The presentation of iatrogenic CAA in older adults widens the known potential spectrum of this disease and highlights the difficulties of making the diagnosis in this age group, and particularly in differentiating iatrogenic from sporadic CAA. Increased vigilance for cases presenting at an older age is essential for furthering our understanding of the clinical phenotype and broader implications of iatrogenic CAA.

Is CAA a perivascular brain clearance disease? A discussion of the evidence to date and outlook for future studies

The brain's network of perivascular channels for clearance of excess fluids and waste plays a critical role in the pathogenesis of several neurodegenerative diseases including cerebral amyloid angiopathy (CAA). CAA is the main cause of hemorrhagic stroke in the elderly, the most common vascular comorbidity in Alzheimer's disease and also implicated in adverse events related to anti-amyloid immunotherapy. Remarkably, the mechanisms governing perivascular clearance of soluble amyloid β-a key culprit in CAA-from the brain to draining lymphatics and systemic circulation remains poorly understood. This knowledge gap is critically important to bridge for understanding the pathophysiology of CAA and accelerate development of targeted therapeutics. The authors of this review recently converged their diverse expertise in the field of perivascular physiology to specifically address this problem within the framework of a Leducq Foundation Transatlantic Network of Excellence on Brain Clearance. This review discusses the overarching goal of the consortium and explores the evidence supporting or refuting the role of impaired perivascular clearance in the pathophysiology of CAA with a focus on translating observations from rodents to humans. We also discuss the anatomical features of perivascular channels as well as the biophysical characteristics of fluid and solute transport.

Uncommon Causes of Nontraumatic Intracerebral Hemorrhage

Nontraumatic intracerebral hemorrhage is an important health issue. Although common causes such as hypertension and cerebral amyloid angiopathy predominantly affect the elderly, there exists a spectrum of uncommon etiologies that contribute to the overall incidence of intracerebral hemorrhage. The identification of these rare causes is essential for targeted clinical management, informed prognostication, and strategic secondary prevention where relevant. This topical review explores the uncommon intracerebral hemorrhage causes and provides practical clues for their clinical and imaging identification. By expanding the clinician's differential diagnosis, this review aims to bridge the gap between standard intracerebral hemorrhage classification systems and the nuanced reality of clinical practice.

Recurrent Intracerebral Haematomas Due to Amyloid Angyopathy after Lyodura Transplantation in Childhood

The number of published cases of presumed iatrogenic cerebral amyloid angiopathy (iCAA) due to the transmission of amyloid β during neurosurgery is slowly rising. One of the potential ways of transmission is through a cadaveric dura mater graft (LYODURA) exposure during neurosurgery. This is a case of a 46-year-old female patient with no chronic conditions who presented with recurrent intracerebral haemorrhages (ICHs) without underlying vessel pathology. Four decades prior, the patient had a neurosurgical procedure with documented LYODURA transplantation. Brain biopsy confirmed CAA. This is a rare case of histologically proven iCAA after a documented LYODURA transplantation in childhood. Our case and already published iCAA cases emphasize the need for considering neurosurgery procedure history as important data in patients who present with ICH possibly related to CAA.

When Atrial Fibrillation Meets Cerebral Amyloid Angiopathy: Current Evidence and Strategies

Non-valvular atrial fibrillation (AF) and cerebral amyloid angiopathy (CAA) are two common diseases in elderly populations. Despite the effectiveness of oral anticoagulant therapy in cardioembolic stroke prevention, intracranial hemorrhage represents the most serious complication of these therapies. Cerebral amyloid angiopathy is one of the main risk factors for spontaneous intracranial bleeding, and this risk is highly increased by age and concomitant antithrombotic therapies. Cerebral amyloid angiopathy can be silent for years and then manifest with clinical features simulating TIA (TIA-mimics) or stroke in AF patients, pushing clinicians to rapidly start VKAs or DOACs, thus increasing the risk of intracranial bleeding if the diagnosis of CAA was unknown. Because the cerebral amyloid angiopathy is easily diagnosed with non-contrast MRI, suspecting the disease can avoid catastrophic complications. In this review, we will provide physicians managing anticoagulant therapies with key tips to familiarize themselves with cerebral amyloid angiopathy, with a focus on the possible clinical presentations and on the diagnostic criteria.

Mechanistic Intimate Insights into the Role of Hydrogen Sulfide in Alzheimer's Disease: A Recent Systematic Review

In the rapidly evolving field of Alzheimer's Disease (AD) research, the intricate role of Hydrogen Sulfide (H2S) has garnered critical attention for its diverse involvement in both pathological substrates and prospective therapeutic paradigms. While conventional pathophysiological models of AD have primarily emphasized the significance of amyloid-beta (Aβ) deposition and tau protein hyperphosphorylation, this targeted systematic review meticulously aggregates and rigorously appraises seminal contributions from the past year elucidating the complex mechanisms of H2S in AD pathogenesis. Current scholarly literature accentuates H2S's dual role, delineating its regulatory functions in critical cellular processes-such as neurotransmission, inflammation, and oxidative stress homeostasis-while concurrently highlighting its disruptive impact on quintessential AD biomarkers. Moreover, this review illuminates the nuanced mechanistic intimate interactions of H2S in cerebrovascular and cardiovascular pathology associated with AD, thereby exploring avant-garde therapeutic modalities, including sulfurous mineral water inhalations and mud therapy. By emphasizing the potential for therapeutic modulation of H2S via both donors and inhibitors, this review accentuates the imperative for future research endeavors to deepen our understanding, thereby potentially advancing novel diagnostic and therapeutic strategies in AD.

Exploratory mass spectrometry of cerebrospinal fluid from persons with autopsy-confirmed LATE-NC

Background

Common neuropathologies associated with dementia include Alzheimer's disease neuropathologic change (ADNC) and limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC). Biofluid proteomics provides a window into the pathobiology of dementia and the information from biofluid tests may help guide clinical management.

Methods

Participants were recruited from a longitudinal cohort of older adults at the University of Kentucky AD Research Center. A convenience sample of clinically obtained lumbar puncture cerebrospinal fluid (CSF) samples was analyzed from 29 older adults that had autopsy confirmation of the presence or absence of LATE-NC. Nine of the participants had autopsy-confirmed LATE-NC. Antemortem CSF specimens were analyzed in two separate processes: From one group, aliquots were depleted of highly abundant proteins using affinity spin columns. Tryptic digests of sample proteins were subjected to liquid chromatographic separation and mass spectrometry using an Eksigent Ekspert nanoLC 400 system in line with a Sciex 6600+ mass spectrometer. Protein identification was performed using Protein Pilot (Sciex, ver. 5) software, and relative quantification was performed using the SWATH processing microApp in PeakView and MarkerView software (Sciex), respectively. Following data analyses, additional studies were performed using western blots.

Results

A total of 830 proteins were identified in the samples depleted of abundant proteins, and 730 proteins were identified in the non-depleted samples. Whereas some dementia-related proteins were detected (Aβ peptide and α-synuclein protein), others were not (TDP-43, TMEM106B, and tau proteins). When the Bonferroni correction was applied to correct for multiple comparisons, only 4 proteins showed differential expression (LATE-NC vs non-LATE-NC) in the nondepleted samples (RBP4, MIF, IGHG3 and ITM2B), whereas none showed statistically different changes in the depleted samples. Post-hoc western blots confirmed that RBP4 expression was higher in the LATE-NC cases at the group level, but there was overlap between the levels of RBP4 in LATE-NC and non-LATE-NC cases.

Conclusions

An exploratory assessment of CSF proteomes of autopsy-confirmed LATE-NC and non-LATE-NC cases from a community-based cohort failed to demonstrate a clear-cut proteomic fingerprint that distinguished the two groups. There was intriguing increase in RBP4 protein levels in CSF from LATE-NC cases. This may provide clues about pathogenetic mechanisms in LATE-NC.