Expression of semaphorin 3A, semaphorin 7A and their receptors in multiple sclerosis lesions

Background:

Studies in multiple sclerosis (MS) and in experimental models point to a critical role of semaphorin (sema)3A and sema7A in MS pathogenesis.

Objective:

The objective of this paper is to characterise the expression of sema3A, sema7A, and their receptors in MS lesions.

Methods:

We included 44 demyelinating lesions from MS patients, 12 lesions with acute cerebral infarct, 11 lesions with progressive multifocal leucoencephalopathy and 10 non-neurological control patients. MS lesions were classified according to inflammatory activity and all samples were immunostained for sema3A, sema7A, neuropilin 1 (Np-1), α1-integrin, and β1-integrin.

Results:

In MS-damaged white matter sema3A and Np-1 were both detected in microglia/macrophages, whereas reactive astrocytes expressed only sema3A. Otherwise, sema7A, α1-integrin and β1-integrin were observed in reactive astrocytes, and microglia/macrophages only expressed β1-integrin. The expression of sema3A, sema7A and their receptors is more relevant in MS than in other demyelinating diseases. Sema3A and sema7A expression correlated with the inflammatory activity of the MS lesions, suggesting their involvement in the immunological process that takes place in MS.

Conclusions:

The expression pattern of sema3A, sema7A and their receptors in MS lesions suggests that both molecules contribute to create a negative environment for tissue regeneration, influencing the ability to regenerate the damaged tissue.

[Clinico-pathological and molecular aspects of diagnostic and prognostic value in gliomas]

INTRODUCTION

Diffuse infiltrative gliomas, the most common primary brain tumours, account for almost 80% of malignant brain tumours. 60-70% of gliomas are astrocytic and over 80% of these tumours is considered high grade malignancy (grade III and IV) according to current World Health Organization classification. Infiltrating gliomas include diffuse astrocytomas, oligodendrogliomas and oligoastrocytomas.

AIM

To review the clinical and histological features of cerebral gliomas, and molecular alterations that add relevant information for novel approaches in diagnosis, prognosis and treatment.

DEVELOPMENT

The current gold standard diagnosis of these tumours relies on histopathological classification, which provides a grading of malignancy as a predictor of biological behaviour. However emerging molecular abnormalities have been discovered in the last years and these molecular changes are playing an increasingly prominent role as predictive biomarkers or in the development of diagnostic and prognostic. Now the neuropathologist is in crossroads between pathology and molecular biology and he plays a significant role in implementation of treatments and/or clinical trials.

CONCLUSIONS

The study of proteomics and molecular biomarkers should complement the histopathological analysis and sometimes allows to determine direct or indirect predictive factors as well as the study of affected pathways which may become selective therapeutic targets.

Brain contusions induce a strong local overexpression of MMP-9. Results of a pilot study

BACKGROUND

Brain contusions are inflammatory evolutive lesions that induce intracranial pressure increase and edema, contributing to neurological outcome. Matrix metalloproteinases (MMPs) 2 and 9 can degrade the majority of the extracellular matrix components, and are implicated in blood-brain barrier disruption and edema formation. The aim of this study was to investigate MMP-2 and MMP-9 profiles in human brain contusions using zymography.

METHODS

A prospective study was conducted in 20 traumatic brain injury patients where contusion brain tissue was resected. Brain tissues from lobectomies were used as controls. Brain homogenates were analysed by gelatin zymography and in situ zimography was performed to confirm results, on one control and one brain contusion tissue sample.

FINDINGS

MMP-2 and MMP-9 levels were higher in brain contusions when compared to controls. MMP-9 was high during the first 24 hours and at 48 to 96 hours, whereas MMP-2 was slightly high at 24 to 96 hours. In situ zymography confirmed gelatin zymography results. A relation between outcome and MMP-9 levels was found; MMP-9 levels were higher in patients with worst outcome.

CONCLUSIONS

Our results indicate strong time-dependent gelatinase expression primarily from MMP-9, suggesting that the inflammatory response induced by focal lesions should be considered as a new therapeutic target.

Metallothionein expression in the central nervous system of multiple sclerosis patients

Multiple sclerosis (MS) is a major chronic demyelinating and inflammatory disease of the central nervous system (CNS) in which oxidative stress likely plays a pathogenic role in the development of myelin and neuronal damage. Metallothioneins (MTs) are antioxidant proteins induced in the CNS by tissue injury, stress and some neurodegenerative diseases, which have been postulated to play a neuroprotective role. In fact, MT-I+II-deficient mice are more susceptible to developing experimental autoimmune encephalomyelitis (EAE), and treatment of Lewis rats with Zn-MT-II reduces EAE severity. We show here that, as in EAE, MT-I+II proteins were expressed in brain lesions of MS patients. Cells expressing MT-I+II were mainly astrocytes and activated monocytes/macrophages. Interestingly, the levels of MT-I+II were slightly increased in the inactive MS lesions in comparison with the active lesions, suggesting that MTs may be important in disease remission.

Adult-onset subacute sclerosing panencephalitis: clinico-pathological findings in 2 new cases

Subacute sclerosing panencephalitis (SSPE), an uncommon disease usually affecting children and adolescents, is caused by persistent measles infection that progresses to chronic infection with fatal outcome. The debut of this disease in adults is rare, with a small number of cases in the medical literature. This article presents the clinical, radiologic and post-mortem neuropathologic findings in 2 new cases of women with SSPE (1 of them during pregnancy), which showed very atypical clinical characteristics, presentation and evolution. The influence of pregnancy on the course of the disease was unfavorable, in keeping with earlier reports. Our patients showed a very prolonged biphasal clinical course, with a period of disease-free remission that lasted several years. Histological study disclosed features of inflammatory disease associated with others of a neurodegenerative nature, such as the formation of neurofibrillary tangles, which would relate SSPE with other tauopathies.

Neonatal tumors of the CNS: a report of 9 cases and a review

Neonatal central nervous system (CNS) tumors are an uncommon and histologically heterogeneous group of neoplasms with different clinical and biological features from those arising in childhood. We report 9 cases in which a diagnosis of CNS tumor was confirmed by biopsy or autopsy during the years 1982-1997 in the Vall d'Hebrón Children's Hospital, Barcelona. Two cases were fetal tumors detected by fetal sonography, 3 patients were symptomatic in the first days after birth and 4 patients presented initial clinical signs in the first weeks or months of life. Eight lesions were supratentorial and 1 was located in the spinal cord. According to histologic types, there were 2 glioneuronal tumors, 1 anaplastic astrocytoma, 1 choroid plexus carcinoma, 1 immature teratoma, 1 craniopharyngioma, 1 hemangioblastoma, 1 astroblastoma and 1 hemangioendothelioma. Extensive review of the literature indicates that our cases of hemangioblastoma, astroblastoma and hemangioendothelioma are exceptional and one more of the very rare and isolated previously published cases.

[Hypertrophic pachymeningitis. A review of the histories of two cases and pathological relationship with the Tolosa-Hunt syndrome and the orbital pseudotumor]

INTRODUCTION

Hypertrophic pachymeningitis is an infrequent condition which starts with a thickening of the dura mater and whose pathogenesis is unknown. We present two new cases of unknown aetiology.

CLINICAL CASE

Case 1. A 53 year old man complained of occipital headache, tinnitus and deafness since February 1981. In October 1981 he was admitted to hospital with a worse headache, perio-orbital pain, dysgeusia and ipsilateral peripheral facial palsy. In December he had generalized tonic-clonic seizures and paralysis of the VII and XI right cranial nerves and IX, X and XII left cranial nerves. In February 1982 he developed right trigeminal neuralgia. He was readmitted in November 1983 with continuous headache, vomiting and a behavior disorder. On CT there was marked attenuation of the posterior dura mater, which the neurosurgical department considered unsuitable for biopsy. He died in March 1985. On necropsy there was hypertrophic pachymeningitis. Case 2. A 62 year old patient consulted in November 1995 complaining of right hypoacusia for the past six months, progressively accompanied by ipsilateral paralysis of the II, IV, VI, VII and VIII cranial nerves but with no other alterations on physical examination. Analytical and serological investigations were normal. Cranial MR showed an extraparenchymatous infiltrating lesion in the middle cranial fossa. Biopsy was decided on when no clinical improvement was seen with corticosteroid treatment. The pathologist reported hypertrophic pachymeningitis. Treatment was started with cyclophosphamide in monthly doses and the condition has remained stable to date.

CONCLUSION

With these two cases we wish to establish a pathogenic relation between the Tolosa-Hunt syndrome and orbital pseudotumor and show the role played by immunosuppressive treatment in the control of hypertrophic pachymeningitis.

[Disseminated acute encephalomyelitis with fatal evolution: clinicopathological study]

INTRODUCTION

Disseminated acute encephalomyelitis is a monophasic demyelinating disease which progresses rapidly and is often fatal. It is an autoimmune condition, mediated by T lymphocytes, in which the immune response is directed against the myelin antigens.

CLINICAL CASE

We describe the clinical, radiological and neuropathological findings in the case of a 31 year old woman who, ten days after complaining of a clinical condition of upper respiratory tract inflammation, presented with unilateral focal neurological signs, subsequent rapid deterioration of consciousness and death. On autopsy the neuropathological characteristics of disseminated acute encephalomyelitis were seen.

CONCLUSIONS

The relative rarity of this condition at the present time makes clinical diagnosis difficult. The differential diagnosis with other conditions may be difficult also. Thus, this disease often leads to a neuropathological diagnosis.

[The CNS amyloid]

INTRODUCTION

In this article we wish to review the most relevant pathogenic aspects and histological characteristics of the deposition of amyloid in the central nervous system (CNS).

DEVELOPMENT

The beta A4, a product of protein APP, codified on chromosome 21, is related to sporadic cerebral amyloid angiopathy not associated with dementia, Alzheimer's disease, senile dementia of Alzheimer type or Down's syndrome, whilst a specific mutation on the 693 codon of the gene which codifies beta-APP is related to hereditary haemorrhage with Dutch-type amyloid angiopathy. The gene which codifies cystatin C, a member of the family of cystatin genes grouped on chromosome 20p11.2, undergoes specific mutation giving rise to a mutant protein which, at the position 68, substitutes leucine for glutamine. The mutant cystatin C has a greater tendency to aggregation when the temperature is increased. This pathogenic molecular mechanism underlies cases of amyloidosis due to hereditary type cystatin C, considered to be a systemic amylosidosis. The formation and deposition of amyloid may also occur in other neurodegenerative diseases of animals and humans in relation to the accumulation of abnormal isoforms of the prion protein, especially in Gerstman-Straussler-Scheinke's disease and the Japanese type of prion cerebral amyloid angiopathy. The fact that these aberrant isoforms mostly undergo conformational changes involving a shift from alpha-helix to beta-sheet structure is basic to the amyloidogenesis of prion disease.

CONCLUSIONS

Amyloid is a family of proteins which is physically, chemically and structurally related, with common histochemical characteristics. In the CNS it is deposited in the vessel walls and parenchyma with topographic patterns and morphological differences according to the different disorders in which the amyloid is involved. Only neuropathological studies will enable us to discover its true incidence in senility with or without clinical features of dementia, and with or without haemorrhagic changes.