Hereditary Cerebral Hemorrhage with Amyloidosis-Dutch Type (HCHWA-D): I - A Review of Clinical, Radiologic and Genetic Aspects

Hereditary cerebral hemorrhage with amyloidosis - Dutch type (HCHWA-D) is an autosomal dominant disease caused by deposition of β-amyloid in the leptomeningeal arteries and cortical arterioles, in addition to preamyloid deposits and amyloid plaques in the brain parenchyma.
The disease is due to a point mutation at codon 693 of the amyloid precursor protein (βPP) gene at chromosome 21. Since this point mutation is diagnostic for HCHWA-D, presymptomatic testing is feasible and offered, together with genetic counselling and psychological support, to subjects at risk. HCHWA-D is clinically characterized by recurrent strokes, in addition to dementia, which can occur after the first stroke but also preceding it. Radiological studies revealed focal lesions (hemorrhages, hemorrhagic and non-hemorrhagic infarctions) and diffuse white matter damage. Diffuse white matter hyperintensities on MRI are an early symptom of HCHWA-D since they have been found on MRI scans of subjects who had not suffered a stroke.
The presence of the diagnostic point mutation makes HCHWA-D a useful model to study the effects of cerebral amyloid angiopathy in vivo. The characteristic pathological abnormalities and its implications for Alzheimer's disease will be discussed in Part II of this article     

Amyloid beta protein (Abeta) starts to deposit as plasma membrane-bound form in diffuse plaques of brains from hereditary cerebral hemorrhage with amyloidosis-Dutch type, Alzheimer disease and nondemented aged subjects

To clarify where and how beta-amyloid begins to deposit in senile plaques, we examined the ultrastructural localization of amyloid beta protein (Abeta) in diffuse plaques of brains with hereditary cerebral hemorrhage with amyloidosis-Dutch type. Alzheimer disease (AD), and from nondemented aged subjects. Serial ultrathin sections of osmium-plastic blocks were immunogold-labeled for Abetax-42 (Abeta42), and sections on grids were observed under the electron microscope (EM) after observing the exact localization of the diffuse plaques in sections on glass slides by the reflection contrast microscope. Abeta42 deposition, which was decollated with gold particles, appeared in 3 forms in all subjects under the EM: 1) Scattered small bundles of amyloid fibrils between cell processes, frequently seen in the densely stained area of diffuse plaques. 2) Scattered small foci of nonfibrillar materials between cell processes as a relatively minor form. 3) Abeta42 on a part of the cell surface plasma membrane of normal appearing cell processes, a major form in weakly immunostained areas. The last form was not associated with degenerative neurites or reactive glia. Abeta42 deposition on the cell surface plasma membrane appears to be an initial event in diffuse plaques, and then it develops into amorphous/fibrillar amyloid between cell processes.     

Nephrotoxicity and Kidney Transport Assessment on 3D Perfused Proximal Tubules

Proximal tubules in the kidney play a crucial role in reabsorbing and eliminating substrates from the body into the urine, leading to high local concentrations of xenobiotics. This makes the proximal tubule a major target for drug toxicity that needs to be evaluated during the drug development process. Here, we describe an advanced in vitro model consisting of fully polarized renal proximal tubular epithelial cells cultured in a microfluidic system. Up to 40 leak-tight tubules were cultured on this platform that provides access to the basolateral as well as the apical side of the epithelial cells. Exposure to the nephrotoxicant cisplatin caused a dose-dependent disruption of the epithelial barrier, a decrease in viability, an increase in effluent LDH activity, and changes in expression of tight-junction marker zona-occludence 1, actin, and DNA-damage marker H2A.X, as detected by immunostaining. Activity and inhibition of the efflux pumps P-glycoprotein (P-gp) and multidrug resistance protein (MRP) were demonstrated using fluorescence-based transporter assays. In addition, the transepithelial transport function from the basolateral to the apical side of the proximal tubule was studied. The apparent permeability of the fluorescent P-gp substrate rhodamine 123 was decreased by 35% by co-incubation with cyclosporin A. Furthermore, the activity of the glucose transporter SGLT2 was demonstrated using the fluorescent glucose analog 6-NBDG which was sensitive to inhibition by phlorizin. Our results demonstrate that we developed a functional 3D perfused proximal tubule model with advanced renal epithelial characteristics that can be used for drug screening studies.     

Secondary microvascular degeneration in amyloid angiopathy of patients with hereditary cerebral hemorrhage with amyloidosis, Dutch type (HCHWA-D)

Various secondary microvascular degenerative and inflammatory alterations may complicate cerebral amyloid angiopathy (CAA) and contribute to the morbidity of CAA-associated stroke. We have investigated the severity of CAA-associated microangiopathy in a genetically determined Dutch form of CAA (HCHWA-D) that has major similarities to the type of CAA that more commonly occurs with aging or Alzheimer’s disease (AD). The presence and extent of the following vascular abnormalities was assessed: (1) hyalinization/fibrosis, (2) microaneurysm formation, (3) chronic (especially lymphocytic) inflammation, (4) perivascular multinucleated giant cells/granulomatous angiitis, (5) macrophages/histiocytes within the vessel wall, (6) vessel wall calcification, (7) fibrinoid necrosis, and (8) mural or occlusive thrombi. (Of these, calcification of CAA-affected vessel walls has, to our knowledge, been described in only a single patient with CAA-associated cerebral hemorrhage.) Some of the changes, such as histiocytes in blood vessel walls and the relationship of vascular hyalinosis to amyloid β/A4 protein deposition, were highlighted by immunohistochemistry. By assessing the numbers of sections in which the changes were present for each case, a ‘score’ reflective of CAA-associated angiopathy could be obtained. This ‘score’ was reproducible among several observers. We suggest that it might also be applicable to quantifying severe CAA and related microvascular degenerative changes in patients with AD. β/A4 immunoreactivity was often sparse and adventitial (or almost absent) in severely hyalinized arterioles and microaneurysms. However, macrophages were prominent in the walls of such vessels and may play a role in the pathogenesis and progression of CAA-related microvasculopathy. Received: 18 June 1997 / Revised, accepted: 22 September 1997     

Patient with eosinophilic polymyositis

In a 36-year-old patient with a severe polymyositis peripheral eosinophilia and abundant infiltration of muscle tissue by eosinophilic granulocytes were observed. Eosinophilic polymyositis was diagnosed. Treatment consisted of high dose prednisone, immunoglobulin and azathioprine, resulting in complete remission of the disease. Idiopathic eosinophilic polymyositis is an uncommon disorder, first described in 1976. The eosinophilic granulocyte is essential in the pathogenesis (by releasing toxic mediators and the production of cytokines), but the cause of the activation is still unknown. Treatment is aimed at immune suppression and consists first of all in administration of prednisone.     

Inclusion body myositis

The clinical features of inclusion body myositis (IBM) were of minor importance in the design of consensus diagnostic criteria, mainly because of controversial views on the specificity of signs and symptoms, although some authors reported "typical" signs. To re–assess the clinical spectrum of IBM, a single investigator using a standard protocol studied a cohort of 64 patients cross–sectionally. Symptom onset was before the age of 50 years in 20% of cases. Only a few patients (14 %) started with weakness other than that of quadriceps, finger flexor or pharyngeal muscles. The sequence of power loss was erratic, but onset of symptoms with quadriceps weakness predicted an earlier onset of dysphagia in older patients (≥ 56 years) compared with younger ones (< 56 years) (p = 0.02). Despite widespread weakness patients had favourable scores on three commonly used function scales and they kept their employment. Complete wheel–chair dependency was rare (3 %). A dominant characteristic was the anatomical distribution of afflicted muscles: ventral extremity muscle groups were more affected than dorsal muscle groups and girdle muscles were least affected, the latter preserving postural stability. Ankylosis, especially in extension of the fingers,was frequently present. Together with the sparing of intrinsic hand muscles it was helpful in the preservation of many skilful movements. IBM has a unique distribution of muscle weakness. Ankylotic contractures are common. We feel that their joint impact on daily functioning is characteristic for the disease.     

In situ transformation of glass-ionomer into an enamel-like material

PURPOSE: To assess the nature of clinically detectable alterations in glass-ionomer after long-term clinical service. METHODS: In addition to clinical macro pictures, SEM was carried out on replicas and on two sectioned primary molars SEM-EDAX analysis was performed to determine chemical transformation in the glass-ionomer. Also with SEM-EDAX, the composition was determined of a partially removed half-year old sealant. RESULTS: The clinically observed altered optical aspect and increased hardness could be related with surface structure changes as identified by SEM. The changed glass-ionomer showed a continuous integration with the adjacent enamel. The SEM-EDAX analysis revealed an increase of calcium and phosphorus in the surface layer, tentatively suggesting a sort of additional "mineralization" of the material. This phenomenon was only observed for restorations that had minimally 2-3 years in vivo dwell time.     

Latent Cerebral Venous and Sinus Thrombosis

The incidence of cerebral venous and sinus thrombosis (CVST) is still unknown. Several assumptions of the incidence have been made. In the one and only series of consecutive brain autopsies series by Towbin in1973 CVST was found in 10,9 % of patients aged 60 years or more. These findings suggest that the true incidence of CVST is higher than generally thought, but there are no other reports supporting these findings. Therefore in order to determine the incidence of latent CVST we conducted a new prospective post mortem study. All brain autopsies performed in our hospital between 1996 and 1998 on patients 60 years of age or older were examined for the presence of CVST in a prospective way. We examined the sagittal sinus, the torcula, the straight sinus, both transverse sinuses, and both sigmoideal sinuses for the presence of thrombosis. The clinical condition, medication, brain-imaging results, clinical cause of death, general findings from the body autopsy and definite cause of death were recorded. Additionally we requested the annual mortality figures of CVST at the department of the National Agency for Statistics of the Netherlands (CBS). A consecutive and prospective series of 102 brain autopsies was performed in our general hospital during a period of two years. We found one case of latent CVST in our series of 102 patients. Comparison with the findings of Towbin using a chi-square test yielded a significant difference in the incidence of latent CVST (χ₂ = 7.65, p < 0.01) between the two studies. The present autopsy study demonstrates that latent CVST is rare. Received: 7 June 2002, Received in revised form: 14 October 2002, Accepted: 21 October 2002 Correspondence to H. P. Bienfait, MD     

Ultrastructural evidence of early non-fibrillar Aβ42 in the capillary basement membrane of patients with hereditary cerebral hemorrhage with amyloidosis, Dutch type

The C-terminal profile and ultrastructure of small and presumably early capillary amyloid β protein (Aβ) deposits were investigated in four patients with hereditary cerebral hemorrhage with amyloidosis, Dutch type. The C terminus of the 40 (Aβ40) or the 42 (Aβ42) amino acid form of Aβ was gold labeled in serial, ultrathin sections on glass slides for reflection contrast microscopy and on grids for electron microscopy. In all studied subjects, reflection contrast microscopy revealed capillaries with focal Aβ42 immunolabeling in the absence of Aβ40 labeling. In the adjacent electron microscopic section, Aβ42 labeling was confined to the capillary basement membrane. The majority of Aβ42⁺40^– deposits showed no amyloid fibrils. Aβ42⁺40^– deposits were sometimes observed in an unremarkable basement membrane but usually showed increased electron density and reticular structures. A small subset of Aβ42⁺40^– deposits with basement membrane changes showed few amyloid fibrils. Aβ42⁺40⁺ capillary deposits always showed definite fibrils and were larger than Aβ42⁺40^– capillary deposits. The present findings suggest that in capillaries the accumulation and subsequent polymerization of Aβ42, possibly in conjunction with basement membrane changes, precedes the definite fibril formation with Aβ40. Received: 9 June 1999 / Accepted: 9 September 1999     

Presence of immunoreactive beta-endorphin in human skin

The production and its induction by ultraviolet radiation (UVR) of proopiomelanocortin (POMC)-derived peptides by keratinocytes has been reported, albeit not consistently. Recently we demonstrated that only under specific culturing conditions human keratinocytes are capable of producing a beta-endorphin (betaE)-like peptide with the characteristics of beta-lipotropin (betaLPH). Here the presence and UV-induction of betaE-immunoreactivity (betaE-IR) in keratinocytes in human skin in vivo was investigated. betaE-IR was detectable by immunohistochemistry in keratinocytes of the follicular matrix and to some extent in cells of sweat ducts, but was absent from epidermal keratinocytes. Absence of betaE-IR was confirmed by radioimmunoassay of HPLC-fractionated extracts of normal epidermis. Repeated exposure to solar-simulated UVR had no effect. This investigation is the first to demonstrate the presence of betaE-immunoreactive material in the follicular matrix of corporal hairs and in duct cells of sweat glands. The possible meaning of these results is discussed.