Topography of Cortical Microbleeds in Alzheimer's Disease with and without Cerebral Amyloid Angiopathy: A Post-Mortem 7.0-Tesla MRI Study

Cortical microbleeds (CMBs) detected on T2*-weighted gradient-echo (GRE) magnetic resonance imaging (MRI) are considered as a possible hallmark of cerebral amyloid angiopathy (CAA). The present post-mortem 7.0-tesla MRI study investigates whether topographic differences exist in Alzheimer's brains without (AD) and with CAA (AD-CAA). The distribution of CMBs in thirty-two post-mortem brains, consisting of 12 AD, 8 AD-CAA and 12 controls, was mutually compared on T2*-GRE MRI of six coronal sections of a cerebral hemisphere. The mean numbers of CMBs were determined in twenty-two different gyri. As a whole there was a trend of more CMBs on GRE MRI in the prefrontal section of the AD, the AD-CAA as well as of the control brains. Compared to controls AD brains had significantly more CMBs in the superior frontal, the inferior temporal, the rectus and the cinguli gyrus, and in the insular cortex. In AD-CAA brains CMBs were increased in all gyri with exception of the medial parietal gyrus and the hippocampus. AD-CAA brains showed a highly significant increase of CMBs in the inferior parietal gyrus (p value: 0.001) and a significant increase in the precuneus and the cuneus (p value: 0.01) compared to the AD brains. The differences in topographic distribution of CMBs between AD and AD-CAA brains should be further investigated on MRI in clinically suspected patients.

Iron deposits in post-mortem brains of patients with neurodegenerative and cerebrovascular diseases: a semi-quantitative 7.0 T magnetic resonance imaging study

BACKGROUND AND PURPOSE

Accumulation of iron (Fe) is often detected in brains of people suffering from neurodegenerative diseases. However, no studies have compared the Fe load between these disease entities. The present study investigates by T2*-weighted gradient-echo 7.0 T magnetic resonance imaging (MRI) the Fe content in post-mortem brains with different neurodegenerative and cerebrovascular diseases.

METHODS

One hundred and fifty-two post-mortem brains, composed of 46 with Alzheimer's disease (AD), 37 with frontotemporal lobar degeneration (FTLD), 11 with amyotrophic lateral sclerosis, 13 with Lewy body disease, 14 with progressive supranuclear palsy, 16 with vascular dementia (VaD) and 15 controls without a brain disease, were examined. The Fe load was determined semi-quantitatively on T2*-weighted MRI serial brain sections in the claustrum, caudate nucleus, putamen, globus pallidus, thalamus, subthalamic nucleus, hippocampus, mamillary body, lateral geniculate body, red nucleus, substantia nigra and dentate nucleus. The disease diagnosis was made on subsequent neuropathological examination.

RESULTS

The Fe load was significantly increased in the claustrum, caudate nucleus and putamen of FTLD brains and to a lesser degree in the globus pallidus, thalamus and subthalamic nucleus. In the other neurodegenerative diseases no Fe accumulation was observed, except for a mild increase in the caudate nucleus of AD brains. In VaD brains no Fe increase was detected.

CONCLUSIONS

Only FTLD displays a significant Fe load, suggesting that impaired Fe homeostasis plays an important role in the pathogenesis of this heterogeneous disease entity.

Efficiency of 5-ALA mediated photodynamic therapy on hypoxic prostate cancer: a preclinical study on the Dunning R3327-AT2 rat tumor model

OBJECTIVES

To evaluate photodynamic therapy (PDT) using 5-ALA-induced protoporphyrin IX (PPIX) in an in vivo hypoxic tumor model and its monitoring using MRI.

MATERIAL AND METHODS

Dunning R3327-AT2 tumors were grafted in the neck of Copenhagen rats. PDT using 150 mg 5-ALA/kg i.v. was performed by focal interstitial illumination of the photosensitized tumor (λ=633 nm; fluence=100 J/cm(2)). MRI at baseline and 2 days after treatment (T1, T2 and dynamic gadolinium enhanced sequences) were performed. Necrosis volumes were determined on post-procedure MRI. Tumors were resected 2 days post-PDT and obtained necrosis was determined histopathologically. Intra-tumoral PPIX distribution was evaluated using confocal microscopy and tissue porphyrin quantification.

RESULTS

Twenty rats were treated divided into three groups: continuous (n=7), fractionated illumination (n=7), and a control group receiving only light or only ALA or neither (n=6). Baseline MRI confirmed the hypoxic character of tumors. Necrosis volumes determined on posttreatment MRI were not reproducible and presented with important geometric and volumetric variability. Average necrosis volumes of 0.39 cc (0-0.874 cc) in the continuous group, 0.24 cc (0.107-0.436 cc) in the fractionated group and 0.012 cc (0-0.071 cc) in the control group were observed. Intra-tumoral PPIX distribution was heterogeneous and PPIX quantification revealed low intra-tumoral concentration.

CONCLUSION

Necrosis volumes induced by 5-ALA-mediated PDT were highly variable and non reproducible, probably because of lack of intra-tissular oxygen. Photosensitizer was poorly represented inside the tumor and its distribution was heterogeneous. Our study suggests that 5-ALA-mediated PDT might not be the best management option for hypoxic prostatic adenocarcinoma.

Hippocampal microbleed on a post-mortem t(2)∗-weighted gradient-echo 7.0-tesla magnetic resonance imaging?

The present post-mortem study of a brain from an Alzheimer patient showed on a T₂∗-weighted gradient-echo 7.0-T MRI of a coronal brain section a hyposignal in the hippocampus, suggesting a microbleed. On the corresponding histological examination, only iron deposits around the granular cellular layer and in blood vessel walls of the hippocampus were observed without evidence of a bleeding. This case report illustrates that the detection of microbleeds on MRI has to be interpreted with caution.

Biomechanical wall properties of human intracranial aneurysms resected following surgical clipping (IRRAs Project)

BACKGROUND AND PURPOSE

Individual rupture risk assessment of intracranial aneurysms is a major issue in the clinical management of asymptomatic aneurysms. Aneurysm rupture occurs when wall tension exceeds the strength limit of the wall tissue. At present, aneurysmal wall mechanics are poorly understood and thus, risk assessment involving mechanical properties is inexistent. Aneurysm computational hemodynamics studies make the assumption of rigid walls, an arguable simplification. We therefore aim to assess mechanical properties of ruptured and unruptured intracranial aneurysms in order to provide the foundation for future patient-specific aneurysmal risk assessment. This work also challenges some of the currently held hypotheses in computational flow hemodynamics research.

METHODS

A specific conservation protocol was applied to aneurysmal tissues following clipping and resection in order to preserve their mechanical properties. Sixteen intracranial aneurysms (11 female, 5 male) underwent mechanical uniaxial stress tests under physiological conditions, temperature, and saline isotonic solution. These represented 11 unruptured and 5 ruptured aneurysms. Stress/strain curves were then obtained for each sample, and a fitting algorithm was applied following a 3-parameter (C(10), C(01), C(11)) Mooney-Rivlin hyperelastic model. Each aneurysm was classified according to its biomechanical properties and (un)rupture status.

RESULTS

Tissue testing demonstrated three main tissue classes: Soft, Rigid, and Intermediate. All unruptured aneurysms presented a more Rigid tissue than ruptured or pre-ruptured aneurysms within each gender subgroup. Wall thickness was not correlated to aneurysmal status (ruptured/unruptured). An Intermediate subgroup of unruptured aneurysms with softer tissue characteristic was identified and correlated with multiple documented risk factors of rupture.

CONCLUSION

There is a significant modification in biomechanical properties between ruptured aneurysm, presenting a soft tissue and unruptured aneurysms, presenting a rigid material. This finding strongly supports the idea that a biomechanical risk factor based assessment should be utilized in the to improve the therapeutic decision making.

Mis-splicing of Tau exon 10 in myotonic dystrophy type 1 is reproduced by overexpression of CELF2 but not by MBNL1 silencing

Tau is the proteinaceous component of intraneuronal aggregates common to neurodegenerative diseases called Tauopathies, including myotonic dystrophy type 1. In myotonic dystrophy type 1, the presence of microtubule-associated protein Tau aggregates is associated with a mis-splicing of Tau. A toxic gain-of-function at the ribonucleic acid level is a major etiological factor responsible for the mis-splicing of several transcripts in myotonic dystrophy type 1. These are probably the consequence of a loss of muscleblind-like 1 (MBNL1) function or gain of CUGBP1 and ETR3-like factor 1 (CELF1) splicing function. Whether these two dysfunctions occur together or separately and whether all mis-splicing events in myotonic dystrophy type 1 brain result from one or both of these dysfunctions remains unknown. Here, we analyzed the splicing of Tau exons 2 and 10 in the brain of myotonic dystrophy type 1 patients. Two myotonic dystrophy type 1 patients showed a mis-splicing of exon 10 whereas exon 2-inclusion was reduced in all myotonic dystrophy type 1 patients. In order to determine the potential factors responsible for exon 10 mis-splicing, we studied the effect of the splicing factors muscleblind-like 1 (MBNL1), CUGBP1 and ETR3-like factor 1 (CELF1), CUGBP1 and ETR3-like factor 2 (CELF2), and CUGBP1 and ETR3-like factor 4 (CELF4) or a dominant-negative CUGBP1 and ETR-3 like factor (CELF) factor on Tau exon 10 splicing by ectopic expression or siRNA. Interestingly, the inclusion of Tau exon 10 is reduced by CUGBP1 and ETR3-like factor 2 (CELF2) whereas it is insensitive to the loss-of-function of muscleblind-like 1 (MBNL1), CUGBP1 and ETR3-like factor 1 (CELF1) gain-of-function, or a dominant-negative of CUGBP1 and ETR-3 like factor (CELF) factor. Moreover, we observed an increased expression of CUGBP1 and ETR3-like factor 2 (CELF2) only in the brain of myotonic dystrophy type 1 patients with a mis-splicing of exon 10. Taken together, our results indicate the occurrence of a mis-splicing event in myotonic dystrophy type 1 that is induced neither by a loss of muscleblind-like 1 (MBNL1) function nor by a gain of CUGBP1 and ETR3-like factor 1 (CELF1) function but is rather associated to CUGBP1 and ETR3-like factor 2 (CELF2) gain-of-function.

Comparison of 7.0-T T₂*-magnetic resonance imaging of cerebral bleeds in post-mortem brain sections of Alzheimer patients with their neuropathological correlates

BACKGROUND

In view of the increasing recognition of cerebral microbleeds (MCBs) with MRI, there is a need to validate their detection in post-mortem brains in patients with cerebrovascular diseases and dementia.

MATERIALS AND METHODS

Out of 20 post-mortem brains of patients with Alzheimer dementia and with different cerebrovascular lesions, 45 large sections of the cerebral hemispheres, brainstem and cerebellum were submitted to a 7.0-T T₂*-weighted MRI, and afterwards compared to the histological detection of haematomas, MCBs and mini-bleeds (MNBs).

RESULTS

The sensitivity, specificity, predictive positive value and predictive negative value of the T₂* imaging to detect MCBs and MNBs were excellent for those in the cortico-subcortical regions. There was a significant overestimation of MNBs in the striatum due to iron deposits unrelated to old haemorrhages. Also in the deep white matter, 42% of MNBs were not detected, while 31% of T₂* hyposignals were not due to MNBs but to vessels filled with post-mortem thrombi.

CONCLUSIONS

When evaluating the 'bleeding load' with 7.0-T T₂*-weighted MRI in post-mortem brain sections of patients with dementia and vascular risk factors, only quantification of small cerebral bleeds in the cortico-subcortical regions is reliable.

The impact of cerebral amyloid angiopathy on the occurrence of cerebrovascular lesions in demented patients with Alzheimer features: a neuropathological study

OBJECTIVE

The aim of this neuropathological study was to determine the prevalence of the different cerebrovascular lesions to be attributed to cerebral amyloid angiopathy (CAA) and of those associated with the severity of the Alzheimer dementia (AD) itself.

PATIENTS AND METHODS

The cerebrovascular lesions were compared separately in 40 brains of patients with mild and 50 with severe AD features. In the two groups, the number of lesions were compared between the brains with severe and those with mild of absent CAA.

RESULTS

The age of the patients, the vascular risk factors and antithrombotic treatment were similar in all the compared groups. The brains with mild and severe AD features and with CAA contained more haematomas, cortical micro-infarcts and micro-bleeds, and more severe white matter changes, and cortico-subcortical and white matter mini-bleeds. In the CAA brains with severe AD features, also more cortical territorial infarcts were observed, compared to those with mild AD features.

CONCLUSIONS

The increase in cortical infarcts cannot be attributed to the CAA alone, but also to the severity of the degenerative features, implying additional vascular factors in the pathogenesis of AD.

Meningioma of the cavernous sinus in a child: case report and review of the literature

Meningiomas infrequently develop in children, and their clinical picture is somewhat different than in adults. We describe here a case of a meningioma in a 9-year-old girl unusual in two aspects. Firstly, it arose from the cavernous sinus what is exceptional in children. Secondly, despite the big tumor mass the child was almost asymptomatic. The only symptoms at presentation were a slight facial asymmetry and minimal laterodeviation of her mandible. Those symptoms had not been noticed by her parents and were detected during careful routine dental examination. The clinical course was quite aggressive and several neurosurgical interventions were necessary. This case underlines the importance of careful medical and dental examination during routine checkup consultations and undertaking necessary diagnostic procedures aimed at elucidating of all detected, even minimal abnormalities.

Alzheimer disease with cerebrovascular disease and vascular dementia: clinical features and course compared with Alzheimer disease

OBJECTIVE

Vascular dementia (VaD) and Alzheimer disease with cerebrovascular disease (AD+CVD) are the leading causes of dementia after Alzheimer disease alone (AD). Little is known about the progression of either VaD or AD+CVD. The aim of this study was to compare demographic features, cognitive decline and survival of patients with VaD, AD+CVD and AD alone attending a memory clinic.

METHODS

This study included 970 patients who were followed at the Lille-Bailleul memory clinic, France. Cognitive functions were measured with the Mini Mental State Examination (MMSE) and the Dementia Rating Scale (DRS). Survival rate was analysed with a left-truncated Cox model. Analyses were adjusted for age, sex, education, hypertension, diabetes and baseline MMSE and DRS.

RESULTS

Of 970 patients, 141 had VaD, 663 AD alone and 166 AD+CVD. The latter were significantly older than AD or VaD patients at onset (71 (SD 7) vs 69 (9) and 68 (9) years, p = 0.01) and at first visit (75 (6) vs 73 (8) and 72 (8) years, p = 0.0002). Baseline MMSE and DRS evaluations were highest for VaD compared with AD alone or AD+CVD patients (p<0.006). Cognitive decline during follow-up was slowest for VaD, intermediate for AD+CVD and fastest for AD alone (p = 0.03). After adjustment, compared with AD patients, mortality risk was similar for those with VaD (relative mortality risk (RR) = 0.7 (0.5 to 1.1)) and tended to be lower for AD+CVD (RR = 0.7 (0.5 to 1.0)). The shorter the delay between first symptoms and first visit, the longer patients survived.

CONCLUSION

This clinical cohort study shows that patients with VaD, AD+CVD and AD present different characteristics at baseline and during follow-up, and underlines the need to distinguish between them.

Cognitive decline and survival in Alzheimer's disease according to education level

OBJECTIVE

We tested the hypothesis that a higher education level is associated with faster cognitive decline and lower survival in a cohort of 670 Alzheimer's disease patients, followed for 3.5 years at the Lille-Bailleul memory centre.

METHODS

The patients were categorized in 3 groups according to educational levels: low (<or=8 years), intermediate (9-12 years) and high (>12 years). Cognitive function was measured with the Mini Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (DRS). Survival was analyzed with a Cox model. Analyses were adjusted for age, sex, cholinesterase inhibitor treatment, diabetes, hypertension, visible vascular lesions on MRI, baseline DRS and MMSE.

RESULTS

The adjusted mixed random model showed that MMSE declined faster for patients with high and intermediate educational levels compared with those with a low educational level (p < 0.0001). The mean annually adjusted DRS decline was highest for the groups with the most education (p = 0.05). The mortality risk was not higher in the better-educated groups (high vs. low: RR = 0.84; 95% CI = 0.35-1.99, intermediate vs. low: RR = 0.82; 95% CI = 0.41-1.63).

CONCLUSION

In our cohort, highly educated patients had a faster cognitive decline than less educated patients but similar mortality rates. Our findings support the cognitive reserve hypothesis.

Overexpression of MBNL1 fetal isoforms and modified splicing of Tau in the DM1 brain: two individual consequences of CUG trinucleotide repeats

Neurofibrillary degeneration is often observed in the brain of patients with type 1 myotonic dystrophy (DM1). It consists principally of the aggregation of Tau isoforms that lack exon 2/3 encoded sequences, and is the consequence of the modified splicing of Tau pre-mRNA. In experimental models of DM1, the splicing of several transcripts is modified due to the loss of Muscleblind-like 1 (MBNL1) function. In the present study, we demonstrate that the MBNL1 protein is also present in the human brain, and consists of several isoforms, as shown by RT-PCR and sequencing. In comparison with controls, we show that the adult DM1 brain exhibits modifications in the splicing of MBNL1, with the preferential expression of long MBNL1 isoforms--a splicing pattern similar to that seen in the fetal human brain. In cultured HeLa cells, the presence of long CUG repeats, such as those found in the DM1 mutation, leads to similar changes in the splicing pattern of MBNL1, and the localization of MBNL1 in nuclear RNA foci. Long CUG repeats also reproduce the repression of Tau exon 2/3 inclusion, as in the human disease, suggesting that their effect on MBNL1 expression may lead to changes in Tau splicing. However, while an overall reduction in the expression of MBNL1 mimics the effect of the DM1 mutation, none of the MBNL1 isoforms tested so far modulates the endogenous splicing of Tau. The modified splicing of Tau thus results from a possibly CUG-mediated loss of function of MBNL1, but not from changes in the MBNL1 expression pattern.

[Phenotypic aspects of FKRP-linked muscular dystrophy type 2I in a series of eleven patients]

INTRODUCTION

Limb-girdle muscular dystrophy type 2I (LGMD2I) is caused by mutations in the fukutin related protein gene (FKRP gene). This study tries to evaluate clinical, biological and mutational characteristics of LGMD2I.

PATIENTS AND METHODS

Eleven patients belonging to 9 families from the North of France were selected. We reported demographic data, and results of muscular testing, cardiac, and respiratory examination, as well as the histopathological features of muscle tissue and a genetic analysis of FKRP gene for each patient.

RESULTS

There were 6 females and 5 males. Mean age at onset was 9.7 years old. Six had Duchenne like phenotype, 5 Becker like phenotype. Nine patients suffered from restrictive respiratory failure, two males had severe dilated cardiomyopathy. Ten patients had the common L276I mutation. Three mutations had not been previously identified: L322V, L489R and R275G heterozygous mutations associated with the L276I mutation.

CONCLUSION

This study underlines inter and intra familial phenotypic variability in LGMD2I, preponderance of cardiomyopathy in males and restrictive respiratory insufficiency in female.

'Cap myopathy': case report of a family

We report the observation of an 18-year-old girl, whose clinical presentation was very suggestive of a congenital myopathy with neonatal onset. A congenital myopathy had been already diagnosed in her brother and in addition her half-cousin died diagnosed with a severe nemaline myopathy at age 4 years. A muscle biopsy performed on both siblings revealed histological and ultrastructural features of 'cap myopathy'. This case report suggests that 'cap myopathy' and some cases of nemaline myopathy with neonatal onset might be two phenotypic expressions of the same genetic disorder. These two entities could therefore, perhaps, be regarded as 'Z-line disorders' possibly caused by defective myofibrillogenesis.

Similar brain tau pathology in DM2/PROMM and DM1/Steinert disease

Neurofibrillary degeneration (NFD) occurs in the brains of patients with myotonic dystrophy (DM) type 1. The authors report a similar tau pathology in the CNS of a patient with DM2 and compare it to that of patients with DM1. A reduced expression of tau exon 2 and exon 3 epitopes is observed in both DM1 and DM2. This suggests a similar physiopathologic process that may contribute to common neurologic features in patients with DM.

ERG and anatomical abnormalities suggesting retinopathy in dementia with Lewy bodies

The authors used flash electroretinography to demonstrate dysfunction of the photopic and scotopic retina in patients with dementia with Lewy bodies and visual hallucinations (VHs) compared with patients with Parkinson disease, patients without VHs, and controls. The retinal dysfunction may be related to slight alteration of the photoreceptors and numerous pale inclusions in the outer plexiform layer found at the post mortem examination, suggesting a specific retinopathy.

[Parkinson's disease, progressive lumbar kyphosis and focal paraspinal myositis]

INTRODUCTION

The camptocormia (bent spine) is characterized by a severe forward flexion of the thoracolumbar spine which disappears in the supine position. Clinical case. We describe a typical case observed in a parkinsonian patient. The MRI, electromyogram and biopsy of the paraspinal muscles revealed a typical myositis pattern.

DISCUSSION

This case, the sixth published to our knowledge, confirms that focal myositis is associated with the camptocormia in Parkinson's disease. Typically it is observed in male subjects, appearing 4 to 6 years after the onset of Parkinson's disease, in fluctuating patients treated by an association of L-Dopa and agonist. It appears quickly and becomes the most important symptom. Antiparkinsonian drugs are useless.

CONCLUSION

This exceptional picture raises original pathophysiological and therapeutic questions. Systematic studies should be performed in order to detail the pathophysiological link between these 3 entities: Parkinson's disease, focal myositis and camptocormia.

[Nasal fossae hemangiopericytoma revealed by acute dacryocystitis]

We report a 42-year-old woman with a hemangiopericytoma tumor located in nasal fossae, revealed by acute dacryocystitis. Clinical rhinoscopic examination and orbitofacial tomodensitometry showed tumefaction of the lacrimal sac and nasolacrimal duct. We removed the tumor by endonasal surgery. The anatomopathology examination confirmed the diagnosis of hemangiopericytoma. The internal canthus area and the maxillary sinus roof were treated with complementary irradiation.

Patients with familial partial lipodystrophy of the Dunnigan type due to a LMNA R482W mutation show muscular and cardiac abnormalities

Diseases due to mutations in the lamin A/C gene (LMNA) are highly heterogeneous, including neuromuscular and cardiac dystrophies, lipodystrophies, and premature ageing syndromes. In this study we characterized the neuromuscular and cardiac phenotypes of patients bearing the heterozygous LMNA R482W mutation, which is the most frequent genotype associated with the familial partial lipodystrophy of the Dunnigan type (FPLD). Fourteen patients from two unrelated families, including 10 affected subjects, were studied. The two probands had been referred for lipoatrophy and/or diabetes. Lipodystrophy, exclusively observed in LMNA-mutated patients, was of variable severity and limited to postpubertal subjects. Lipodystrophy and metabolic disturbances were more severe in women, even if an enlarged neck was a constant finding. The severity of hypertriglyceridemia and hirsutism in females was related to that of insulin resistance. Clinical muscular alterations were only present in LMNA-mutated patients. Clinical and histological examination showed an invalidating, progressive limb-girdle muscular dystrophy in a 42-yr-old woman that had been present since childhood, associated with a typical postpubertal FPLD phenotype. Six of eight adults presented the association of calf hypertrophy, perihumeral muscular atrophy, and a rolling gait due to proximal lower limb weakness. Muscular histology was compatible with muscular dystrophy in one of them and/or showed a nonspecific excess of lipid droplets (in three cases). Immunostaining of lamin A/C was normal in the six muscular biopsies. Surprisingly, calpain 3 expression was undetectable in the patient with the severe limb-girdle muscular dystrophy, although the gene did not reveal any molecular alterations. At the cardiac level, cardiac septal hypertrophy and atherosclerosis were frequent in FPLD patients. In addition, a 24-yr-old FPLD patient had a symptomatic second degree atrioventricular block. In conclusion, we showed that most lipodystrophic patients affected by the FPLD-linked LMNA R482W mutation show muscular and cardiac abnormalities. The occurrence and severity of the myopathic and lipoatrophic phenotypes varied and were not related. The muscular phenotype was evocative of limb girdle muscular dystrophy. Cardiac hypertrophy and advanced atherosclerosis were frequent. FPLD patients should receive careful neuromuscular and cardiac examination whatever the underlying LMNA mutation.