Brain pathology
-
Brain endothelial cells have unique properties in terms of barrier function, local molecular signaling, regulation of local cerebral blood flow (CBF) and interactions with other members of the neurovascular unit. In cerebral small vessel disease (arteriolosclerosis; SVD), the endothelial cells in small arteries survive, even when mural pathology is advanced and myocytes are severely depleted. Here, we review aspects of altered endothelial functions that have been implicated in SVD: local CBF dysregulation, endothelial activation and blood-brain barrier (BBB) dysfunction. ⋯ Some groups find that computational analyses of magnetic resonance imaging (MRI) scans, following systemic injection of a gadolinium-based contrast agent, suggest that extravasation into brain parenchyma is heightened in people with SVD. Our recent histochemical studies of donated brain tissue, using immunolabeling for large plasma proteins [fibrinogen, immunoglobulin G (IgG)], do not support an association of SVD with recent plasma protein extravasation. It is possible that a trigger leakage episode, or a size-selective loosening of the BBB, participates in SVD pathology.
-
CADASIL and CARASIL are hereditary small vessel diseases leading to vascular dementia. CADASIL commonly begins with migraine followed by minor strokes in mid-adulthood. Dominantly inherited CADASIL is caused by mutations (n > 230) in NOTCH3 gene, which encodes Notch3 receptor expressed in vascular smooth muscle cells (VSMC). ⋯ CARASIL is caused by mutations (presently n = 10) in high-temperature requirement. A serine peptidase 1 (HTRA1) gene, which result in reduced function of HTRA1 as repressor of transforming growth factor-β (TGF β) -signaling. Cerebral arteries show loss of VSMCs and marked hyalinosis, but not stenosis.
-
Small vessel diseases (SVDs) of the brain are likely to become increasingly common in tandem with the rise in the aging population. In recent years, neuroimaging and pathological studies have informed on the pathogenesis of sporadic SVD and several single gene (monogenic) disorders predisposing to subcortical strokes and diffuse white matter disease. However, one of the limitations toward studying SVD lies in the lack of consistent assessment criteria and lesion burden for both clinical and pathological measures. ⋯ Important significant regional differences in lesion location within the brain may enable one to distinguish SVDs, where frontal lobe involvement appears consistently with almost every SVD, but others bear specific pathologies in other lobes, such as the temporal pole in CADASIL and the pons in pontine autosomal dominant microangiopathy and leukoencephalopathy or PADMAL. Additionally, degenerative changes in the vascular smooth muscle cells, the cerebral endothelium and the basal lamina are often rapid and more aggressive in genetic disorders. Further quantification of other microvascular elements and even neuronal cells is needed to fully characterize SVD pathogenesis and to differentiate the usefulness of vascular interventions and treatments on the resulting pathology.
-
Neuromyelitis optica (NMO) is an inflammatory neurologic disease clinically characterized by severe optic neuritis (ON) and transverse myelitis (TM). The relationship between NMO and multiple sclerosis (MS) has long been a matter of debate. However, the discovery of an NMO-specific autoantibody, NMO-immunoglobulin G/aquaporin 4 (AQP4) antibody, has dramatically advanced our understanding of the disease, and the clinical, magnetic resonance imaging (MRI), optical coherence tomography, and laboratory examinations have clarified unique features of NMO that are distinct from MS. ⋯ Immunosuppressive treatments are effective for acute attacks and prevention of relapses of NMOSD, and new molecularly targeted drugs are under investigation. Importantly, some disease modifying drugs for MS may exacerbate NMOSD, making early differential diagnosis of the two diseases crucial. We review the evolving clinical spectrum, the updated clinical, MRI, neuro-ophthalmological and laboratory findings, and the current status of treatment in NMOSD.
-
Glioblastoma is the most common type of primary brain tumor in adults and is among the most lethal and least successfully treated solid tumors. Recently, research into the area of stem cells in brain tumors has gained momentum. ⋯ Initially, we consider GSCs at a morphological and cellular level, and then discuss important cell markers, signaling pathways and genetics. Furthermore, we highlight the difficulties associated with what some of the evidence indicates and what collectively the studies contribute to further defining the interpretation of GSCs.