Amplification of protease-activated receptors signaling in sporadic cerebral cavernous malformation endothelial cells.

In the central nervous system, thrombin-mediated activation of protease-activated receptors (PARs) results in neuroinflammation and increased vascular permeability. These events have been linked to cancer and neurodegeneration. Endothelial cells (ECs) isolated from sporadic cerebral cavernous malformation (CCM) specimens showed dysregulation of genes involved in "thrombin-mediated PAR-1 activation" signaling. CCM is a vascular disease involving brain capillaries. In CCM, ECs show defective cell junctions. Oxidative stress and neuroinflammation play a key role in disease onset and progression. In order to confirm the possible role of thrombin pathway in sporadic CCM pathogenesis, we evaluated PARs expression in CCM-ECs. We found that sporadic CCM-ECs overexpress PAR1, PAR3 and PAR4, together with other coagulation factor encoding genes. Moreover, we investigated about expression of the three familial CCM genes (KRIT1, CCM2 and PDCD10) in human cerebral microvascular ECs, following thrombin exposure, as well as protein level. Thrombin exposure affects EC viability and results in dysregulation of CCM gene expression and, then, in decreased protein level. Our results confirm amplification of PAR pathway in CCM suggesting, for the first time, the possible role of PAR1-mediated thrombin signaling in sporadic CCM. Thrombin-mediated PARs over activation results in increased blood-brain barrier permeability due to loss of cell junction integrity and, in this context, also the three familial CCM genes may be involved.

Deciphering impact of single nucleotide polymorphisms on cotranscriptional modification in CCM gene mRNAs.

Novel insights on regulation of gene expression mechanisms highlight the pivotal role of epitranscriptomic modifications on decision about transcript fate. These modifications include methylation of adenosine and cytosine in RNA molecules. Impairment of the normal epitranscriptome profile was observed in several pathological conditions, such as cancer and neurodegeneration. However, it is still unknown if alteration of this regulatory mechanism can be involved in cerebral cavernous malformation (CCM) development. CCM is a rare genetic condition affecting brain microvasculature, resulting from mutations in the three genes KRIT1, CCM2, and PDCD10. By data integration of association study, in silico prediction, and gene expression analysis, we evaluated role of single nucleotide polymorphisms (SNPs) highly recurrent in patients with CCM, on CCM gene expression regulation. Results showed that several of these SNPs lead to a drastic downexpression, in KRIT1 and CCM2 genes and this downregulation can be due to alteration of epitranscriptome profile, occurring these SNPs in gene regions that are subject to epitranscriptome modifications. These data suggest that this novel mechanism of gene expression regulation can be consider to further investigation on CCM pathogenesis.

Editome landscape of CCM-derived endothelial cells.

By regulating several phases of gene expression, RNA editing modifications contribute to maintaining physiological RNA expression levels. RNA editing dysregulation can affect RNA molecule half-life, coding/noncoding RNA interaction, alternative splicing, and circular RNA biogenesis. Impaired RNA editing has been observed in several pathological conditions, including cancer and Alzheimer's disease. No data has been published yet on the editome profile of endothelial cells (ECs) isolated from human cerebral cavernous malformation (CCM) lesions. Here, we describe a landscape of editome modifications in sporadic CCM-derived ECs (CCM-ECs) by comparing editing events with those observed in human brain microvascular endothelial cells (HBMECs). With a whole transcriptome-based variant calling pipeline, we identified differential edited genes in CCM-ECs that were enriched in pathways related to angiogenesis, apoptosis and cell survival, inflammation and, in particular, to thrombin signalling mediated by protease-activated receptors and non-canonical Wnt signalling. These pathways, not yet associated to CCM development, could be a novel field for further investigations on CCM molecular mechanisms. Moreover, enrichment analysis of differentially edited miRNAs suggested additional small noncoding transcripts to consider for development of targeted therapies.

Imaging features of perineural and perivascular spread in rapidly progressive rhino-orbital-cerebral mucormycosis: A case report and brief review of the literature.

BACKGROUND: Rhinocerebral mucormycosis (ROCM) is an opportunistic fungal infection originating from the paranasal sinuses with extension to the brain. A delayed diagnosis can rapidly result in a poor prognosis. ROCM commonly affects patients with diabetes or immunocompromised states with a variable progression. CASE DESCRIPTION: We report the case of a 59-year old patient with an untreated diabetes who developed a ROCM with rapidly progressive neurological symptoms. From the onset of sinus pain, nasal congestion, he rapidly developed facial swelling and masticatory dysfunction. The patient underwent sinus surgery which allowed Rhizopus oryzae to be isolated. Accordingly, a systemic therapy by intensive intravenous amphotericin B was started. Nevertheless, the infection rapidly resulted in bilateral cavernous sinuses thrombosis and occlusion of the left internal carotid artery providing the subsequent patient death. CONCLUSION: Mucormycosis is a life-threatening fungal infection in diabetic and/or immunosuppressed patients. Our case demonstrates the three main mechanisms for infection spreading that are direct, perineural, and perivascular diffusion. Clear identification of the main risk factors, proper assessment of clinical features, and radiological findings may improve the chance for an early diagnosis and patient survival.

An Unusual But Possible Complication After Endoscopic Third Ventriculostomy.

BACKGROUND: We present an unusual but possible complication after ETV for the treatment of acute hydrocephalus due to malfunction of a previously implanted V-P shunt. CASE DESCRIPTION: A 12-year-old male patient was urgently operated upon by means of an endoscopic third-ventriculostomy and the positioning of a temporary external ventricular catheter because of the malfunction of a previously implanted V-P shunt; immediately after the operation, the tip of the external catheter caused an obstruction of the ostomy, which was resolved with the withdrawn of catheter for circa 1 cm, left closed and ultimately removed after 4 days. The patient did not present any further symptom and remained shunt-free at the last 2-year follow-up visit. CONCLUSIONS: One should consider such occurrence in cases of early ETV failure when a ventricular catheter is left in situ, even though temporarily.

Transcriptome analysis provides new molecular signatures in sporadic Cerebral Cavernous Malformation endothelial cells.

Cerebral cavernous malformations (CCM) are lesions affecting brain capillaries that appear with a mulberry-like morphology. This shape results from the enlarged and tangled microvessels having defective endothelial cell junctions, few surrounding pericytes and dense extracellular collagen-rich matrix. Three genes KRIT1, CCM2 and PDCD10 are linked to disease onset. However, a variable percentage of patients harbour no mutations at these loci, encouraging hypothesis of further genetic factors involved in CCM pathogenesis. Here we present data obtained by transcriptome analysis on endothelial cells isolated by CCM specimens, with the aim to identify dysregulated pathways involved in lesion onset. Lesions belonged to two patients carried neither germline nor somatic mutations at the three CCM genes. By comparison with Human brain microvascular endothelial cells (HBMECs) expression profile, we identified 1325 differentially expressed genes (Bonferroni pValue <0.05) common for the two samples. Functional enrichment analysis clustered these genes in 80 terms related to neuroinflammation, extra-cellular matrix remodelling, cell junction impairment, reactive oxygen species metabolism. In addition, CCM genes expression values resulted slightly altered in only one of the two CCM endothelial cell samples when compared to HBMECs, suggesting as further genetic factors can contribute to CCM development. Following expression analysis, we suggests that the molecular shift from canonical to non-canonical Wnt pathway might be a key event in CCM pathogenesis. Moreover, our results provide novel potential genetic targets to investigate for the development of more selective therapies.

Hirayama disease - Early MRI diagnosis of subacute medullary ischemia: A case report.

BACKGROUND: Hirayama disease (HD) is a rare, benign, and self-limiting motor neuron disorder that results in selective motor impairment of the C7-T1 myotomes. It is characterized by progressive, unilateral, or bilateral asymmetric muscle atrophy of the distal upper extremities and myelopathy. CASE DESCRIPTION: A 23-year-old male presented with bilateral atrophy of the thenar/hypothenar eminences/ interosseous muscles, plus left-hand weakness. The cervical MRI documented subacute ischemic damage of the distal cervical cord. To rule out a tumor and reduce questionable cord compression, the patient underwent a C5-C6 anterior cervical discectomy and fusion (ACDF) immediately followed by a laminectomy with durotomy and to obtain a spinal cord biopsy. When the histology confirmed focal cord ischemia consistent with HD, it was clear that both operations were unnecessary. CONCLUSION: Establishing the diagnosis of HD is based on clinical findings and MRI/flexion MR features which include the demonstration of an increased T2-weighted intramedullary cord signal, enlargement of the posterior epidural space, and segmental spinal cord atrophy. The presence of HD should be recognized as a "nonsurgical entity," and conservative nonsurgical management should be employed.

High-Throughput Sequencing to Detect Novel Likely Gene-Disrupting Variants in Pathogenesis of Sporadic Brain Arteriovenous Malformations.

Molecular signaling that leads to brain arteriovenous malformation (bAVM) is to date elusive and this is firstly due to the low frequency of familial cases. Conversely, sporadic bAVM is the most diffuse condition and represents the main source to characterize the genetic basis of the disease. Several studies were conducted in order to detect both germ-line and somatic mutations linked to bAVM development and, in this context, next generation sequencing technologies offer a pivotal resource for the amount of outputted information. We performed whole exome sequencing on a young boy affected by sporadic bAVM. Paired-end sequencing was conducted on an Illumina platform and filtered variants were validated by Sanger sequencing. We detected 20 likely gene-disrupting variants affecting as many loci. Of these variants, 11 are inherited novel variants and one is a de novo nonsense variant, affecting STK4 gene. Moreover, we also considered rare known variants affecting loci involved in vascular differentiation. In order to explain their possible involvement in bAVM pathogenesis, we analyzed molecular networks at Cytoscape platform. In this study we focus on some genetic point variations detected in a child affected by bAVM. Therefore, we suggest these novel affected loci as prioritized for further investigation on pathogenesis of bAVM lesions.

An unusual internal carotid artery compression as a possible cause of Eagle syndrome - A novel hypothesis and an innovative surgical technique.

BACKGROUND: Eagle syndrome (ES) is a rare symptomatic condition generally caused by an elongated styloid process (SP) or calcification of the stylohyoid complex. On the diagnosis is made, its treatment remains subjective since the indications for surgical intervention are still not standardized. Although styloidectomy is the surgical treatment of choice, no consensus exists regarding the transcervical or/and transoral route. Here, we report our experience in a patient with bilateral internal carotid artery (ICA) dissection caused by ES, who underwent innovative surgical technique. CASE DESCRIPTION: A 53-year-old man, with the right-sided middle cerebral artery acute stroke, underwent computed tomography angiography 3 days after a successful endovascular treatment. The study showed a bilateral ICA dissection with bilateral hypertrophic SPs and a close relationship of ICAs with both SPs anteriorly and C1 transverse process posteriorly. Considering the occurrence of ICA compression by a styloid/C1 transverse process juxtaposition, the patient underwent the left partial C1 transversectomy by an extraoral approach. A temporary paresis of the ipsilateral lower lip lasted 1 month, with a partial remission after 3 months. The patient reported significant improvement of symptoms with a good esthetics and functional outcome. CONCLUSION: A styloid/C1 transverse process juxtaposition should be considered as an alternative pathogenetic mechanism in vascular ES. When a posterior ICA compression by C1 transverse process is present, a bone reshaping of C1 rather than a conventional styloidectomy can be considered an efficacious treatment which allows a good preservation of the styloid muscles and ligaments.

Posttraumatic chronic cranial osteomyelitis due to a superficial wound - A clinical and neuroradiological case report.

BACKGROUND: Osteomyelitis is a progressive infection of bone and bone marrow by microorganisms, resulting in inflammatory destruction of bone, bone necrosis, and new bone formation. Skull involvement is a rare occurrence which mainly affects children with chronic inflammatory diseases of paranasal sinusitis, or malignant otitis. In adults, cranial vault osteomyelitis can occur after cranial surgery or head trauma. CASE DESCRIPTION: We describe an unusual case of chronic cranial osteomyelitis occurred 3 months following a mild traumatic brain injury. The causative mechanisms along with the diagnostic modalities are discussed. CONCLUSION: Focal cranial vault osteomyelitis, in the absence of severe trauma, can be challenging to diagnose. Imaging findings and patient history should be carefully investigated to make a correct diagnosis.

DCE and DSC perfusion MRI diagnostic accuracy in the follow-up of primary and metastatic intra-axial brain tumors treated by radiosurgery with cyberknife.

BACKGROUND: The differential diagnosis between radiation necrosis, tumor recurrence and tumor progression is crucial for the evaluation of treatment response and treatment planning. The appearance of treatment-induced tissue necrosis on conventional Magnetic Resonance Imaging (MRI) is similar to brain tumor recurrence and it could be difficult to differentiate the two entities on follow-up MRI examinations. Dynamic Susceptibility Contrast-enhanced (DSC) and Dynamic Contrast-Enhanced (DCE) are MRI perfusion techniques that use an exogenous, intravascular, non-diffusible gadolinium-based contrast agent. The aim of this study was to compare the diagnostic accuracy of DSC and DCE perfusion MRI in the differential diagnosis between radiation necrosis and tumor recurrence, in the follow-up of primary and metastatic intra-axial brain tumors after Stereotactic RadioSurgery (SRS) performed with CyberKnife. METHODS: A total of 72 enhancing lesions (57 brain metastases and 15 primary brain tumors) were analyzed with DCE and DSC, by means of MRI acquisition performed by 1,5 Tesla MR scanner. The statistical relationship between the diagnosis of tumor recurrence or radiation necrosis, decided according to clinicoradiologically criteria, rCBV and Ktrans was evaluated by the point-biserial correlation coefficient respectively. RESULTS: The statistical analysis showed a correlation between the diagnosis of radiation necrosis or recurrent tumor with Ktrans (rpb = 0.54, p < 0.001) and with rCBV (rpb = 0.37, p = 0.002). The ROC analysis of rCBV values demonstrated a good classification ability in differentiating radiation necrosis from tumour recurrence as well as the Ktrans. The optimal cut-off value for rCBV was k = 1.23 with 0.88 of sensitivity and 0.75 of specificity while for Ktrans was k = 28.76 with 0.89 of sensitivity and 0.97 of specificity. CONCLUSIONS: MRI perfusion techniques, particularly DCE, help in the differential diagnosis by tumor recurrence and radiation necrosis during the follow-up after radiosurgery.

Vis-à-vis: a focus on genetic features of cerebral cavernous malformations and brain arteriovenous malformations pathogenesis.

Cerebrovascular malformations include a wide range of blood vessel disorders affecting brain vasculature. Neuroimaging differential diagnosis can result unspecific due to similar phenotypes of lesions and their deep localization. Next-generation sequencing (NGS) platforms simultaneously analyze several hundreds of genes and can be applied for molecular distinction of different phenotypes within the same disorder's macro-area. We discuss about the main criticisms regarding molecular bases of cerebral cavernous malformations (CCM) and brain arteriovenous malformations (AVM), highlighting both common pathogenic aspects and genetic differences leading to lesion development. Many recent studies performed on human CCM and AVM tissues aim to detect genetic markers to better understand molecular bases and pathogenic mechanism, particularly for sporadic cases. Several genes involved in angiogenesis show different expression patterns between CCM and AVM, and these could represent a valid starting point to project a NGS panel to apply for differential cerebrovascular malformation diagnosis.

UAIS: Unruptured Aneurysms Italian Study.

BACKGROUND: Unruptured intracranial aneurysms (UIAs) are increasingly identified and are an important health-care burden; in the past they were commonly treated by surgical clipping, but nowadays endovascular coil embolization is increasingly employed as an alternative. METHODS: The Unruptured Aneurysms Italian Study (UAIS) is a multicentric cooperative prospective study aimed to delineate the "State of the Art" of UIAs treatment in Italy. 51 Italian Neurosurgical and Neuroradiological Units, representatives of all 20 Italian regions are involved in the Study. RESULTS: UAIS started on June 2003 and ended on July 2007. 1138 patients were collected by that date, but 181 were ruled-out due to severe violation of the protocol; 957 had complete data and could be statistically evaluated. CONCLUSIONS: UAIS demonstrates that the treatment of UAs, as performed in Italy as a Nation, is effective in improving long-term outcome vs. natural history, particularly in aneurysms larger than 7 mm.

Introducing the concept of "CSF-shift edema" in traumatic brain injury.

Brain edema after severe traumatic brain injury (TBI) plays an important role in the outcome and survival of injured patients. It is also one of the main targets in the therapeutic approach in the current clinical practice. To date, the pathophysiology of traumatic brain swelling is complex and, being that it is thought to be mainly cytotoxic and vasogenic in origin, not yet entirely understood. However, based on new understandings of the hydrodynamic aspects of cerebrospinal fluid (CSF), an additional mechanism of brain swelling can be considered. An increase in pressure into the subarachnoid space, secondary to traumatic subarachnoid hemorrhage, would result in a rapid shift of CSF from the cisterns, through the paravascular spaces, into the brain, resulting in an increase of brain water content. This mechanism of brain swelling would be termed as "CSF-shift edema." This "CSF-shift," promoted by a pressure gradient, leads to increased pressure inside the paravascular spaces and the interstitium of the brain, disturbing the functions of the paravascular system, with implications of secondary brain injury. Cisternostomy, an emerging surgical treatment, would reverse the direction of the CSF-shift, allowing for a decrease in brain swelling. In addition, this technique would reduce the pressure in the paravascular spaces and interstitium, leading to a recovery of the functionality of the paravascular system.

Relevance of CCM gene polymorphisms for clinical management of sporadic cerebral cavernous malformations.

Cerebral cavernous malformations (CCMs) are clusters of capillaries in the brain that may cause focal deficits or seizures in affected patients. They occur in both sporadic and inherited autosomal dominant form. Germline mutations in CCM1, CCM2 and CCM3 were identified in familial cases. Over the past 13years we performed sequencing and MLPA of the CCM genes in all sporadic and familial CCM cases coming from some hospital clinics of Neurology and Neurosurgery of Messina and other Italian cities. Our results showed that CCM sporadic patients, negative for previously reported CCM gene causative mutations, always carried known CCM polymorphisms. Previously, we reported polymorphisms in CCM2 gene associated with an increase in risk for CCM. Here, we undertook a case-control study to investigate the possible association of others polymorphisms (c.485+65 C/G, c.989+63 C/G, c.1980 A/G in CCM1 gene, c.472+127 C/T in CCM2 and c.150 G/A in CCM3) with CCMs. The five polymorphisms were characterized in 64 sporadic patients and in 90 healthy controls by ASO-PCR. Statistically significant differences in frequencies between patients and controls were found for c.485+65C/G, c.1980 A/G and c.472+127C/T polymorphisms. For c.485+65C/G polymorphism, a higher frequency of mutated allele (G) was found in patients group (9%) than in controls (2%) (p=0.0041); for c.1980 A/G polymorphism, we found a frequency of mutated allele (G) higher in the control group (25%) compared to that of patients (8%) (p=0.0396). Same trend was observed for c.472+127C/T polymorphism (T allele frequency=34% and 6% in control group and patients, respectively; p=0.0001). Polymorphisms c.485+65C/G, c.1980 A/G and c.472+127C/T were associated with an increased risk of CCM as indicated by odds ratio values. Furthermore, c.1980 A/G and c.472+127C/T polymorphisms were associated with less severe CCM symptomatology. Identification of these polymorphisms in CCM sporadic patient may represent a useful tool for clinicians to determine prognosis, scheduled periodic checks and appropriate treatment strategy.

Role of Hemodynamic Forces in Unruptured Intracranial Aneurysms: An Overview of a Complex Scenario.

BACKGROUND: An understanding of the natural history of unruptured intracranial aneurysms (IAs) has always played a critical role in presurgical or endovascular planning, to avoid possibly fatal events. Size, shape, morphology, and location are known risk factors for rupture of an aneurysm, but morphologic parameters alone may not be sufficient to perform proper rupture risk stratification. METHODS: We performed a systematic PubMed search and focused on hemodynamics forces that may influence aneurysmal initiation, growth, and rupture. RESULTS: We included 223 studies describing several hemodynamic parameters related to aneurysm natural history. In these studies, different modalities of aneurysm model creation have been used to evaluate flow and to comprehensively analyze the evolution of IAs. Controversy exists about the correlation between these parameters and initiation, growth, rupture risk, or stabilization of the aneurysmal sac. Recent findings have also shown the importance of flow patterns in this process and the relationship between unruptured IA geometry and hemodynamic parameters. CONCLUSIONS: The role of hemodynamic forces in evaluation of the natural history of unruptured IAs presents is inherently complex and is still not completely understood. In this complex scenario, although several attempts have been described in the literature, a proper risk rupture stratification and treatment strategy selection based on hemodynamic forces has not yet been created. Further efforts should be made to accomplish this important goal.

Presurgical role of MRI tractography in a case of extensive cervicothoracic spinal ependymoma.

BACKGROUND: Intramedullary spinal ependymoma is a tumor, hardly characterizable with conventional magnetic resonance (MR) imaging only. MR diffusion tensor imaging (DTI) with three-dimensional fiber-tracking reconstructions allows the evaluation of the relationship between neoplasm and white matter fiber tracts, being a powerful tool in presurgical planning. We present DTI findings in a case of a young female with an extensive cervicothoracic spinal ependymoma. CASE DESCRIPTION: The patient complained of a 2-month history of acute urinary retention, weakness and numbness on the lower limbs and the upper left limb. She underwent MR imaging that showed an extensive cervicothoracic spinal mass, difficult to characterize with conventional MR sequences. DTI showed peripherally displacement of fibers, without involvement of the spinal cord, findings consistent with an ependymoma. The patient underwent surgery with a complete resection "en bloc" of the lesion, which showed clear cleavage planes, as detected by DTI. Histopathological findings confirmed the diagnosis of ependymoma. CONCLUSIONS: DTI is a useful tool in presurgical planning, helping in differentiating not infiltrating neoplasms, such as spinal ependymomas, from other infiltrative and more aggressive neoplasms, which are considered not resectable.