Search

In the brains of most adult mammals, neural precursor cells (NPCs) from the subventricular zone (SVZ) migrate through the rostral migratory stream (RMS) to replace olfactory bulb interneurons. Following brain injury, published studies have shown that NPCs can divert from the SVZ-RMS-OB route and migrate toward injured brain regions, but the quantity of arriving cells, the lack of survival and terminal differentiation of neuroblasts into neurons, and their limited capacity to re-connect into circuitry are insufficient to promote functional recovery in the absence of therapeutic intervention. Our lab has fabricated a biomimetic tissue-engineered rostral migratory stream (TE-RMS) that replicates some notable structural and functional components of the endogenous rat RMS. Based on the design attributes for the TE-RMS platform, it may serve as a regenerative medicine strategy to facilitate sustained neuronal replacement into an injured brain region or an in vitro tool to investigate cell-cell communication and neuroblast migration. Previous work has demonstrated that the TE-RMS replicates the basic structure, unique nuclear shape, cytoskeletal arrangement, and surface protein expression of the endogenous rat RMS. Here, we developed an enhanced TE-RMS fabrication method in hydrogel microchannels that allowed more robust and high-throughput TE-RMS assembly. We report unique astrocyte behavior, including astrocyte bundling into the TE-RMS, the presence of multiple TE-RMS bundles, and observations of discontinuities in TE-RMS bundles, when microtissues are fabricated in agarose microchannels containing different critical curved or straight geometric features. We also demonstrate that we can harvest NPCs from the SVZ of adult rat brains and that EGFP+ cells migrate in chain formation from SVZ neurospheres through the TE-RMS in vitro. Overall, the TE-RMS can be utilized as an in vitro platform to investigate the pivotal cell-cell signaling mechanisms underlying the synergy of molecular cues involved in immature neuronal migration and differentiation.

Axonal extension and retraction are ongoing processes that occur throughout all developmental stages of an organism. The ability of axons to produce mechanical forces internally and respond to externally generated forces is crucial for nervous system development, maintenance, and plasticity. Such axonal mechanobiological phenomena have typically been evaluated in vitro at a single-cell level, but these mechanisms have not been studied when axons are present in a bundled three-dimensional (3D) form like in native tissue. In an attempt to emulate native cortico-cortical interactions under in vitro conditions, we present our approach to utilize previously described micro-tissue engineered neural networks (micro-TENNs). Here, micro-TENNs were comprised of discrete populations of rat cortical neurons that were spanned by 3D bundled axonal tracts and physically integrated with each other. We found that these bundled axonal tracts inherently exhibited an ability to generate contractile forces as the microtissue matured. We therefore utilized this micro-TENN testbed to characterize the intrinsic contractile forces generated by the integrated axonal tracts in the absence of any external force. We found that contractile forces generated by bundled axons were dependent on microtubule stability. Moreover, these intra-axonal contractile forces could simultaneously generate tensile forces to induce so-called axonal “stretch-growth” in different axonal tracts within the same microtissue. The culmination of axonal contraction generally occurred with the fusion of both the neuronal somatic regions along the axonal tracts, therefore perhaps showing the innate tendency of cortical neurons to minimize their wiring distance, a phenomenon also perceived during brain morphogenesis. In future applications, this testbed may be used to investigate mechanisms of neuroanatomical development and those underlying certain neurodevelopmental disorders.

There has recently been a resurgence of interest in psychedelic compounds based on studies demonstrating their potential therapeutic applications in treating post-traumatic stress disorder, substance abuse disorders, and treatment-resistant depression. Despite promising efficacy observed in some clinical trials, the full range of biological effects and mechanism(s) of action of these compounds have yet to be fully established. Indeed, most studies to date have focused on assessing the psychological mechanisms of psychedelics, often neglecting the non-psychological modes of action. However, it is important to understand that psychedelics may mediate their therapeutic effects through multi-faceted mechanisms, such as the modulation of brain network activity, neuronal plasticity, neuroendocrine function, glial cell regulation, epigenetic processes, and the gut-brain axis. This review provides a framework supporting the implementation of a multi-faceted approach, incorporating in silico, in vitro and in vivo modeling, to aid in the comprehensive understanding of the physiological effects of psychedelics and their potential for clinical application beyond the treatment of psychiatric disorders. We also provide an overview of the literature supporting the potential utility of psychedelics for the treatment of brain injury (e.g., stroke and traumatic brain injury), neurodegenerative diseases (e.g., Parkinson’s and Alzheimer’s diseases), and gut-brain axis dysfunction associated with psychiatric disorders (e.g., generalized anxiety disorder and major depressive disorder). To move the field forward, we outline advantageous experimental frameworks to explore these and other novel applications for psychedelics.

The translation of therapeutics from lab to clinic has a dismal record in the fields of neurotrauma and neurological disorders [...]

Astrocytes are essential to virtually all brain processes, from ion homeostasis to neurovascular coupling to metabolism, and even play an active role in signaling and plasticity. Astrocytic dysfunction can be devastating to neighboring neurons made inherently vulnerable by their polarized, excitable membranes. Therefore, correcting astrocyte dysfunction is an attractive therapeutic target to enhance neuroprotection and recovery following acquired brain injury. However, the translation of such therapeutic strategies is hindered by a knowledge base dependent almost entirely on rodent data. To facilitate additional astrocytic research in the translatable pig model, we present a review of astrocyte findings from pig studies of health and disease. We hope that this review can serve as a road map for intrepid pig researchers interested in studying astrocyte biology.

Large animal models of spinal cord injury may be useful tools in facilitating the development of translational therapies for spinal cord injury (SCI). Porcine models of SCI are of particular interest due to significant anatomic and physiologic similarities to humans. The similar size and functional organization of the porcine spinal cord, for instance, may facilitate more accurate evaluation of axonal regeneration across long distances that more closely resemble the realities of clinical SCI. Furthermore, the porcine cardiovascular system closely resembles that of humans, including at the level of the spinal cord vascular supply. These anatomic and physiologic similarities to humans not only enable more representative SCI models with the ability to accurately evaluate the translational potential of novel therapies, especially biologics, they also facilitate the collection of physiologic data to assess response to therapy in a setting similar to those used in the clinical management of SCI. This review summarizes the current landscape of porcine spinal cord injury research, including the available models, outcome measures, and the strengths, limitations, and alternatives to porcine models. As the number of investigational SCI therapies grow, porcine SCI models provide an attractive platform for the evaluation of promising treatments prior to clinical translation.

O’Donnell et al. describe their Tissue-Engineered Rostral Migratory Stream (TE-RMS) comprised of human astrocyte-like cells that can be derived from adult gingival stem cells within one week, which reorganizes into bundles of bidirectional, longitudinally-aligned astrocytes to emulate the endogenous RMS. Establishing immature neuronal migration in vitro and in vivo, their study demonstrates surgical feasibility and proof-of-concept evidence for this nascent technology.

Neurocritical care significantly impacts outcomes after moderate-to-severe acquired brain injury, but it is rarely applied in preclinical studies. We created a comprehensive neurointensive care unit (neuroICU) for use in swine to account for the influence of neurocritical care, collect clinically relevant monitoring data, and create a paradigm that is capable of validating therapeutics/diagnostics in the unique neurocritical care space. Our multidisciplinary team of neuroscientists, neurointensivists, and veterinarians adapted/optimized the clinical neuroICU (e.g., multimodal neuromonitoring) and critical care pathways (e.g., managing cerebral perfusion pressure with sedation, ventilation, and hypertonic saline) for use in swine. Moreover, this neurocritical care paradigm enabled the first demonstration of an extended preclinical study period for moderate-to-severe traumatic brain injury with coma beyond 8 h. There are many similarities with humans that make swine an ideal model species for brain injury studies, including a large brain mass, gyrencephalic cortex, high white matter volume, and topography of basal cisterns, amongst other critical factors. Here we describe the neurocritical care techniques we developed and the medical management of swine following subarachnoid hemorrhage and traumatic brain injury with coma. Incorporating neurocritical care in swine studies will reduce the translational gap for therapeutics and diagnostics specifically tailored for moderate-to-severe acquired brain injury.

Abstract Background As part of the multinational I-O Optimise research initiative, this retrospective cohort study of patients with advanced non-small cell lung cancer (NSCLC) evaluated real-world treatment patterns and survival prior to immunotherapy reimbursement in Portugal. Methods This study utilized a database held by IPO-Porto, Portugal’s largest oncology hospital. Adult patients diagnosed with stage IIIB or IV NSCLC from January 2012 to December 2016 at IPO-Porto, with follow-up to June 2017, were included. Treatment analyses were performed from 2015 onwards. Kaplan–Meier methods were used for overall survival (OS). Factors associated with OS and systemic anti-cancer therapy (SACT) treatment were assessed using multivariate statistical models. Results Of 1524 patients diagnosed with NSCLC at IPO-Porto, 1008 patients had advanced disease (stage IIIB: 10.1%, 154/1524, stage IV: 56.0%, 854/1524). For those with advanced disease, median age was 65 years (range: 21–92) and 75.6% (762/1008) were male. Median OS (interquartile range [IQR]) was 11.4 (5.2–26.9) months for stage IIIB and 6.3 (2.4–15.0) months for stage IV. Factors associated with decreased risk of death included female sex and epidermal growth factor receptor gene (EGFR)/anaplastic lymphoma kinase gene (ALK) mutations/rearrangements; factors associated with increased risk of death included older age and stage IV disease. Among patients diagnosed in 2015 or 2016, 75.8% (297/392) received ≥1 line of SACT. Platinum-based chemotherapy was the most common first-line therapy (non-squamous cell carcinoma [NSQ]: 72.9%; squamous cell carcinoma [SQ] 87.3%, 55/63; patients with EGFR/ALK mutations/rearrangements primarily received tyrosine kinase inhibitors). The likelihood of receiving SACT was lower in older patients and those diagnosed with stage IV disease. Patients not receiving SACT had poor survival outcomes (median OS [IQR]: NSQ, 1.8 [1.1–3.1] months; SQ, 2.3 (1.3–3.4) months), while median OS (IQR) in SACT-treated patients was 12.6 (6.1–24.5) months for NSQ and 10.3 (5.7–15.9) months for SQ. Conclusions This real-world data analysis from a large Portuguese oncology hospital demonstrates a high disease burden for advanced NSCLC in the pre-immunotherapy era, with nearly one-quarter of patients not receiving SACT. Even in patients receiving SACT, median survival was only about 1 year.

Following peripheral nerve injury comprising a segmental defect, the extent of axon regeneration decreases precipitously with increasing gap length. Schwann cells play a key role in driving axon re-growth by forming aligned tubular guidance structures called bands of Büngner, which readily occurs in distal nerve segments as well as within autografts – currently the most reliable clinically-available bridging strategy. However, host Schwann cells generally fail to infiltrate large-gap acellular scaffolds, resulting in markedly inferior outcomes and motivating the development of next-generation bridging strategies capable of fully exploiting the inherent pro-regenerative capability of Schwann cells. We sought to create preformed, implantable Schwann cell-laden microtissue that emulates the anisotropic structure and function of naturally-occurring bands of Büngner. Accordingly, we developed a biofabrication scheme leveraging biomaterial-induced self-assembly of dissociated rat primary Schwann cells into dense, fiber-like three-dimensional bundles of Schwann cells and extracellular matrix within hydrogel micro-columns. This engineered microtissue was found to be biomimetic of morphological and phenotypic features of endogenous bands of Büngner, and also demonstrated 8 and 2× faster rates of axonal extension in vitro from primary rat spinal motor neurons and dorsal root ganglion sensory neurons, respectively, compared to 3D matrix-only controls or planar Schwann cells. To our knowledge, this is the first report of accelerated motor axon outgrowth using aligned Schwann cell constructs. For translational considerations, this microtissue was also fabricated using human gingiva-derived Schwann cells as an easily accessible autologous cell source. These results demonstrate the first tissue engineered bands of Büngner (TE-BoBs) comprised of dense three-dimensional bundles of longitudinally aligned Schwann cells that are readily scalable as implantable grafts to accelerate axon regeneration across long segmental nerve defects.

Neurogenesis in the postnatal mammalian brain is known to occur in the dentate gyrus of the hippocampus and the subventricular zone. These neurogenic niches serve as endogenous sources of neural precursor cells that could potentially replace neurons that have been lost or damaged throughout the brain. As an example, manipulation of the subventricular zone to augment neurogenesis has become a popular strategy for attempting to replace neurons that have been lost due to acute brain injury or neurodegenerative disease. In this review article, we describe current experimental strategies to enhance the regenerative potential of endogenous neural precursor cell sources by enhancing cell proliferation in neurogenic regions and/or redirecting migration, including pharmacological, biomaterial, and tissue engineering strategies. In particular, we discuss a novel replacement strategy based on exogenously biofabricated “living scaffolds” that could enhance and redirect endogenous neuroblast migration from the subventricular zone to specified regions throughout the brain. This approach utilizes the first implantable, biomimetic tissue-engineered rostral migratory stream, thereby leveraging the brain's natural mechanism for sustained neuronal replacement by replicating the structure and function of the native rostral migratory stream. Across all these strategies, we discuss several challenges that need to be overcome to successfully harness endogenous neural precursor cells to promote nervous system repair and functional restoration. With further development, the diverse and innovative tissue engineering and biomaterial strategies explored in this review have the potential to facilitate functional neuronal replacement to mitigate neurological and psychiatric symptoms caused by injury, developmental disorders, or neurodegenerative disease.

Objective: The effectiveness of statin therapy in a real life setting may differ from that in clinical trials, as physicians make non-randomised treatment decisions for patients with less uniform and possibly different characteristics. We therefore performed a study to compare the effectiveness of different statins and doses in routine clinical practice with respect to total serum cholesterol and LDL-cholesterol (LDL-C) reduction and goal attainment according to European guidelines on the prevention of cardiovascular disease (CVD).Research design and methods: Naive statin users starting treatment in 2003 and 2004 with LDL-C measurements at baseline and between 30 and 365 days after start of treatment were extracted from the PHARMO database. During treatment with their initial statin dose LDL-C reduction and attainment of cholesterol goals were compared between different statins and doses. Results : Of 2303 identified naive patients, approximately 30% were allocated to the high CVD-risk group. Average LDL-C reductions were 48%, 42%, 39%, and 32% at mean doses of 11 mg rosuvastatin, 17 mg atorvastatin, 22 mg simvastatin and 35 mg pravastatin, respectively. The proportion of patients attaining cholesterol goals was 75% for rosuvastatin, 68% for atorvastatin, 56% for simvastatin, and 42% for pravastatin. Dose comparisons showed greater LDL-C reduction and increased goal attainment for rosuvastatin 10 mg compared to other statins at most doses (adjusted p < 0.05).Conclusions: In a real life setting, both LDL-C reduction and the proportion of patients attaining cholesterol goals appear to be significantly increased among users of rosuvastatin compared to other statins. These results confirm and extend reported clinical trial results to a real world setting. [ABSTRACT FROM AUTHOR]

Objectives To assess how a decade of developments in systematic anticancer therapy (SACT) for advanced non-small cell lung cancer (NSCLC) affected overall survival (OS) in a large UK University Hospital.Design Real-world retrospective observational cohort study using existing data recorded in electronic medical records.Setting A large National Health Service (NHS) university teaching hospital serving 800 000 people living in a diverse metropolitan area of the UK.Participants 2119 adults diagnosed with advanced NSCLC (tumour, node, metastasis stage IIIB or IV) between 2007 and 2017 at Leeds Teaching Hospitals NHS Trust.Main outcomes and measures OS following diagnosis and the analysis of factors associated with receiving SACT.Results Median OS for all participants was 2.9 months, increasing for the SACT-treated subcohort from 8.4 months (2007–2012) to 9.1 months (2013–2017) (p=0.02); 1-year OS increased from 33% to 39% over the same period for the SACT-treated group. Median OS for the untreated subcohort was 1.6 months in both time periods. Overall, 30.6% (648/2119) patients received SACT; treatment rates increased from 28.6% (338/1181) in 2007–2012 to 33.0% (310/938) in 2013–2017 (p=0.03). Age and performance status were independent predictors for SACT treatment; advanced age and higher performance status were associated with lower SACT treatment rates.Conclusion Although developments in SACT during 2007–2017 correspond to some changes in survival for treated patients with advanced NSCLC, treatment rates remain low and the prognosis for all patients remains poor.

New neurons are integrated into the circuitry of the olfactory bulb throughout the lifespan in the mammalian brain—including in humans. These new neurons are born in the subventricular zone and subsequently mature as they are guided over long distances via the rostral migratory stream through mechanisms we are only just beginning to understand. Regeneration after brain injury is very limited, and although some neuroblasts from the rostral migratory stream will leave the path and migrate toward cortical lesion sites, this neuronal replacement is generally not sustained and therefore does not provide enough new neurons to alleviate functional deficits. Using newly discovered microtissue engineering techniques, we have built the first self-contained, implantable constructs that mimic the architecture and function of the rostral migratory stream. This engineered microtissue emulates the dense cord-like bundles of astrocytic somata and processes that are the hallmark anatomical feature of the glial tube. As such, our living microtissue-engineered rostral migratory stream can serve as an in vitro test bed for unlocking the secrets of neuroblast migration and maturation, and may potentially serve as a living transplantable construct derived from a patient's own cells that can redirect their own neuroblasts into lesion sites for sustained neuronal replacement following brain injury or neurodegenerative disease. In this paper, we summarize the development of fabrication methods for this microtissue-engineered rostral migratory stream and provide proof-of-principle evidence that it promotes and directs migration of immature neurons.