Diffuse intrinsic pontine glioma (DIPG) is a type of intrinsic brainstem glial tumor that occurs primarily in the pediatric population. DIPG is initially diagnosed based on clinical symptoms and the characteristic location on imaging. Histologically, these tumors are characterized by a heterogenous population of cells with multiple genetic mutations and high infiltrative capacity. The most common mutation seen in this group is a lysine to methionine point mutation seen at position 27 (K27M) within histone 3 (H3). Tumors with the H3 K27M mutation, are considered grade 4 and are now categorized within the H3 K27-altered diffuse midline glioma category by World Health Organization classification. Due to its critical location and aggressive nature, DIPG is resistant to the most eradicative treatment and is universally fatal; however, modern advances in the surgical techniques resulting in safe biopsy of the lesion have significantly improved our understanding of this disease at the molecular level. Genomic analysis has shown several mutations that play a role in the pathophysiology of the disease and can be targeted therapeutically. In this review, we will elaborate on DIPG from general aspects and the evolving molecular landscape. We will also review innovative therapeutic options that have been trialed along with new promising treatments on the horizon.
Glioblastoma is the most common adult primary brain tumor with near-universal fatality. Major histocompatibility complex (MHC) class I molecules are important mediators of CD8 activation and can be downregulated by cancer cells to escape immune surveillance. MR1 is a nonclassical MHC-I-like molecule responsible for the activation of a subset of T cells. Although high levels of MR1 expression should enhance cancer cell recognition, various tumors demonstrate MR1 overexpression with unknown implications. Here, we study the role of MR1 in glioma. Using multi-omics data from the Cancer Genome Atlas (TCGA), we studied MR1 expression patterns and its impact on survival for various solid tumors. In glioma specifically, we validated MR1 expression by histology, elucidate transcriptomic profiles of MR1 high versus low gliomas. To understand MR1 expression, we analyzed the methylation status of the MR1 gene and MR1 gene-related transcription factor (TF) expression. MR1 is overexpressed in all grades of glioma and many other solid cancers. However, only in glioma, MR1 overexpression correlated with poor overall survival and demonstrated global dysregulation of many immune-related genes in an MR1-dependent manner. MR1 overexpression correlated with decreased MR1 gene methylation and upregulation of predicted MR1 promoter binding TFs, implying MR1 gene methylation might regulate MR1 expression in glioma. Our in silico analysis shows that MR1 expression is a predictor of clinical outcome in glioma patients and is potentially regulated at the epigenetic level, resulting in immune-related genes dysregulation. These findings need to be validated using independent in vitro and in vivo functional studies.
Human neural progenitor cell (NPC) migration within the subventricular zone (SVZ) of the lateral ganglionic eminence is an active process throughout early brain development. The migration of human NPCs from the SVZ to the olfactory bulb during fetal stages resembles what occurs in adult rodents. As the human brain develops during infancy, this migratory stream is drastically reduced in cell number and becomes barely evident in adults. The mechanisms regulating human NPC migration are unknown. The Slit–Robo signaling pathway has been defined as a chemorepulsive cue involved in axon guidance and neuroblast migration in rodents. Slit and Robo proteins expressed in the rodent brain help guide neuroblast migration from the SVZ through the rostral migratory stream to the olfactory bulb. Here, we present the first study on the role that Slit and Robo proteins play in human-derived fetal neural progenitor cell migration (hfNPC). We describe that Robo1 and Robo2 isoforms are expressed in the human fetal SVZ. Furthermore, we demonstrate that Slit2 is able to induce a chemorepellent effect on the migration of hfNPCs derived from the human fetal SVZ. In addition, when Robo1 expression is inhibited, hfNPCs are unable to migrate to the olfactory bulb of mice when injected in the anterior SVZ. Our findings indicate that the migration of human NPCs from the SVZ is partially regulated by the Slit–Robo axis. This pathway could be regulated to direct the migration of NPCs in human endogenous neural cell therapy.
1 August 2017 in Current Opinion in Endocrinology, Diabetes and Obesity
Purpose of review: The pituitary gland is one of the key components of the endocrine system. Congenital or acquired alterations can mediate destruction of cells in the gland leading to hormonal dysfunction. Even though pharmacological treatment for pituitary disorders is available, exogenous hormone replacement is neither curative nor sustainable. Thus, alternative therapies to optimize management and improve quality of life are desired. Recent findings: An alternative modality to re-establish pituitary function is to promote endocrine cell regeneration through stem cells that can be obtained from the pituitary parenchyma or pluripotent cells. Stem cell therapy has been successfully applied to a plethora of other disorders, and is a promising alternative to hormonal supplementation for resumption of normal hormone homeostasis. Summary: In this review, we describe the common causes for pituitary deficiencies and the advances in cellular therapy to restore the physiological pituitary function.
Y/stent, and transcervical carotid revascularization, certain patients are not ideal candidates for any of these modalities. Novel technical advances such as intravascular lithotripsy (Shockwave Medical Inc.) have emerged as a potential treatment modality to treat patients with severely calcified plaques, a well-described limitation for carotid stent expansion and apposition.2-4 The safety and efficacy of intravascular lithotripsy have been demonstrated through select case series and coronary artery disease I‐II‐III studies, culminating in its Food and Drug Administration approval for the management of novo, calcified, stenotic coronary arteries before stent placement.2,5 This technical video presents an illustrative case of a patient with symptomatic severely calcified carotid plaque with previous neck radiation precluding endarterectomy, treated with off-label use of balloon lithotripsy plus stent.6 The patient consented to the procedure....
Ess and safety, but it is critical to consider potential complications. Complications include vascular-related problems such as perforation, occlusion, cerebral hyperperfusion, stent thrombosis, restenosis, and embolic events.3 To date, there is no standardized definition for braid collapse and fish-mouthing; however, braid collapse has been reported to occur at a rate of 1% and the latter at a rate of 3%.4 This technical video presents a case of a 51-year-old woman initially treated with a Surpass Evolve flow diverter (Stryker) for a right ophthalmic aneurysm. Secondary to device malapposition and collapse, she developed recurrent ischemic progressive neurologic impairment symptoms. The braid collapse was treated using a Pipeline Embolization device 3.25 × 20 mm (Medtronic) because this device exhibited a larger partial compressive force when compared with the 64-wire device.5 The procedure was uneventful and significantly improved the patient's neurologic symptoms. This technical video illustrates rescue stenting as a salvage intervention for FD collapse cases. The patient gave informed consent for surgery. Institutional review board approval was deemed unnecessary....