Subcommissural Organ-Spondin-Derived Peptide Restores Memory in a Mouse Model of Alzheimer’s Disease

Alzheimer’s disease (AD) is a devastating neurodegenerative disease that affects millions of older people worldwide and is characterized by a progressive deterioration of cognitive functions, including learning and memory. There are currently very few approved treatments (i.e., acetylcholinesterase inhibitors such as donepezil), all of which are limited to the symptomatic control of AD and are associated with side effects that may result in discontinuation of treatment. Therefore, there is an urgent need to develop disease-modifying treatments to prevent AD-induced cognitive deficits. Subcommissural organ (SCO)-spondin is a brain-specific glycoprotein produced during embryogenesis and has a substantial impact on neuronal development. In the current study, we sought to evaluate the protective effects of the linear (NX210) and cyclized (NX210c) forms of a SCO-spondin-derived peptide on learning and memory in a mouse model of AD. Mice received an intracerebroventricular injection of Aβ25–35 oligomers and were subsequently treated with intraperitoneal injections of vehicle, NX210 or NX210c of different doses (ranging from 0.1 to 30 mg/kg) and therapy paradigms (early or late stand-alone treatments, combination with donepezil or second-line treatment). Cognitive function was evaluated using Y-Maze, step-through latency passive avoidance (STPA) and Morris water maze (MWM) tests for up to 4 months. Early stage daily treatment with NX210 and NX210c decreased the levels of common pathological markers and features of AD, including Aβ1–42, phosphorylated-tau, inflammation, astrogliosis and lipid peroxidation. Meanwhile, use of these drugs increased the levels of synaptophysin and postsynaptic density protein 95. Regardless of the experimental paradigm used, NX210 and NX210c prevented Aβ25–35-induced decrease in spontaneous alternations (Y-Maze) and step-through latency into the dark compartment (STPA), and Aβ25–35-induced increase in time needed to locate the immersed platform during the learning phase and decrease in time spent in the target quadrant during the retention phase (MWM). Interestingly, this study provides the novel evidence that the native and oxidized cyclic forms of the SCO-spondin-derived peptide reduce pathological factors associated with AD and restore learning and memory at both early and late disease stages. Overall, this study sheds light on the therapeutic potential of this innovative disease-modifying peptide to restore memory function in patients with AD.

Papillary Tumor of the Pineal Region: Case Report and Literature Review

Papillary tumor of the pineal region (PTPR) is a neuroectodermal tumor thought to originate from cells of the subcommissural organ. Its oncologic properties are still under investigation, as well as the most suitable therapeutic measures for this type of neoplasm. We report the case of a 36-year-old woman with a 1-year history of headache and intermittent diplopia. The magnetic resonance imaging (MRI) scan showed a heterogeneously enhancing mass in the pineal region that caused an acute hydrocephalus, and an emergency shunt derivation was necessary. One week later, the patient was submitted to subtotal tumor resection, and remained asymptomatic in the post-operative period. In the follow-up, the patient remained asymptomatic; in the imaging control 3.5 years after the surgical resection, local recurrence was identified, and the patient was submitted to a local radiation protocol. Our literature review showed an early clinical onset due to intracranial hypertension signs. Definitive clinical onset might be reached only through a histopathological examination. Gross total resection followed by radiotherapy is the current standard of care. Local recurrence is often observed, with rare dissemination to the cerebral spinal fluid. The natural history of the PTPR remains unknown, as well as the best treatment strategy. Large case series with longer follow-ups are necessary for further conclusions.

Microsurgical decompression of tumor of a rare posterior third ventricular pathology

Of the posterior third ventricular tumors, a papillary tumor of the pineal gland is a rare entity that originates from specialized ependymoma of the subcommissural organ. In this video narration, we present a case of a 33-year-old male with headaches and recent cognitive decline due to a posterior third ventricular lesion. The patient underwent a posterior interhemispheric approach, and a gross-total decompression was achieved with no signs of recurrence in a 2-year follow-up period. With this case we highlight the microsurgical technique employed for decompressing tumors of the posterior third ventricular region with preservation of eloquent structures and draining veins.The video can be found here:https://youtu.be/o0WbyOqmtX0.

Papillary Tumor of the Pineal Region: MR Signal Intensity Correlated to Histopathology

Tumors of the pineal region are rare and can be challenging to differentiate by imaging. Papillary tumor of the pineal region (PTPR) was recently recognized as a neoplasm in the World Health Organization (WHO) 2007 classification, arising from specialized ependymocytes in the subcommissural organ, which is located in the pineal region. It is a rare histological type of pineal tumor with only a few cases reported. Here, we describe a case of histologically confirmed PTPR in a 17-year-old man who presented with a headache. A literature review was performed to clarify the clinical, radiological, and pathological features of PTPR. Pineal neoplasms do not have pathognomonic imaging findings; however, we discuss T1 hyperintensity, which is a key for imaging diagnosis according to recent reports. In particular, if the hyperintensity in T1 is not due to fat, calcification, melanin, or hemorrhage in a mass of the posterior commissure or pineal region, the diagnosis of a PTPR may be suggested, as observed in this case.