scholarly journals Stem Cell Therapy for Neurodegenerative Diseases: How Do Stem Cells Bypass the Blood-Brain Barrier and Home to the Brain?

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yvonne Cashinn Chia ◽  
Clarice Evey Anjum ◽  
Hui Rong Yee ◽  
Yenny Kenisi ◽  
Mike K. S. Chan ◽  
...  

Blood-brain barrier (BBB) is a term describing the highly selective barrier formed by the endothelial cells (ECs) of the central nervous system (CNS) homeostasis by restricting movement across the BBB. An intact BBB is critical for normal brain functions as it maintains brain homeostasis, modulates immune cell transport, and provides protection against pathogens and other foreign substances. However, it also prevents drugs from entering the CNS to treat neurodegenerative diseases. Stem cells, on the other hand, have been reported to bypass the BBB and successfully home to their target in the brain and initiate repair, making them a promising approach in cellular therapy, especially those related to neurodegenerative disease. This review article discusses the mechanism behind the successful homing of stem cells to the brain, their potential role as a drug delivery vehicle, and their applications in neurodegenerative diseases.

2019 ◽  
Vol 11 ◽  
pp. 117957351984065 ◽  
Author(s):  
Divine C Nwafor ◽  
Allison L Brichacek ◽  
Afroz S Mohammad ◽  
Jessica Griffith ◽  
Brandon P Lucke-Wold ◽  
...  

Sepsis is a systemic inflammatory disease resulting from an infection. This disorder affects 750 000 people annually in the United States and has a 62% rehospitalization rate. Septic symptoms range from typical flu-like symptoms (eg, headache, fever) to a multifactorial syndrome known as sepsis-associated encephalopathy (SAE). Patients with SAE exhibit an acute altered mental status and often have higher mortality and morbidity. In addition, many sepsis survivors are also burdened with long-term cognitive impairment. The mechanisms through which sepsis initiates SAE and promotes long-term cognitive impairment in septic survivors are poorly understood. Due to its unique role as an interface between the brain and the periphery, numerous studies support a regulatory role for the blood-brain barrier (BBB) in the progression of acute and chronic brain dysfunction. In this review, we discuss the current body of literature which supports the BBB as a nexus which integrates signals from the brain and the periphery in sepsis. We highlight key insights on the mechanisms that contribute to the BBB’s role in sepsis which include neuroinflammation, increased barrier permeability, immune cell infiltration, mitochondrial dysfunction, and a potential barrier role for tissue non-specific alkaline phosphatase (TNAP). Finally, we address current drug treatments (eg, antimicrobials and intravenous immunoglobulins) for sepsis and their potential outcomes on brain function. A comprehensive understanding of these mechanisms may enable clinicians to target specific aspects of BBB function as a therapeutic tool to limit long-term cognitive impairment in sepsis survivors.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Linan Liu ◽  
Mark A. Eckert ◽  
Hamidreza Riazifar ◽  
Dong-Ku Kang ◽  
Dritan Agalliu ◽  
...  

Systemically infused mesenchymal stem cells (MSCs) are emerging therapeutics for treating stroke, acute injuries, and inflammatory diseases of the central nervous system (CNS), as well as brain tumors due to their regenerative capacity and ability to secrete trophic, immune modulatory, or other engineered therapeutic factors. It is hypothesized that transplanted MSCs home to and engraft at ischemic and injured sites in the brain in order to exert their therapeutic effects. However, whether MSCs possess the ability to migrate across the blood-brain barrier (BBB) that separates the blood from the brain remains unresolved. This review analyzes recent advances in this area in an attempt to elucidate whether systemically infused MSCs are able to actively transmigrate across the CNS endothelium, particularly under conditions of injury or stroke. Understanding the fate of transplanted MSCs and their CNS trafficking mechanisms will facilitate the development of more effective stem-cell-based therapeutics and drug delivery systems to treat neurological diseases and brain tumors.


2018 ◽  
Author(s):  
Matthew J. Stebbins ◽  
Benjamin D. Gastfriend ◽  
Scott G. Canfield ◽  
Ming-Song Lee ◽  
Drew Richards ◽  
...  

ABSTRACTBrain pericytes play an important role in the formation and maintenance of the neurovascular unit (NVU), and their dysfunction has been implicated in central nervous system (CNS) disorders. While human pluripotent stem cells (hPSCs) have been used to model other components of the NVU including brain microvascular endothelial cells (BMECs), astrocytes, and neurons, cells having brain pericyte-like phenotypes have not been described. In this study, we generated neural crest stem cells (NCSCs), the embryonic precursor to forebrain pericytes, from human pluripotent stem cells (hPSCs) and subsequently differentiated NCSCs to brain pericyte-like cells. The brain pericyte-like cells expressed marker profiles that closely resembled primary human brain pericytes, and they self-assembled with endothelial cells to support vascular tube formation. Importantly, the brain pericyte-like cells induced blood-brain barrier (BBB) properties in BMECs, including barrier enhancement and reduction of transcytosis. Finally, brain pericyte-like cells were incorporated with iPSC-derived BMECs, astrocytes, and neurons to form an isogenic human NVU model that should prove useful for the study of the BBB in CNS health, disease, and therapy.


Author(s):  
Yijun Pan ◽  
Joseph Nicolazzo

The access of drugs into the central nervous system (CNS) is regulated by the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB). A large body of evidence supports perturbation of these barriers in neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Modifications to the BBB and BSCB are also reported in amyotrophic lateral sclerosis (ALS), albeit these modifications have received less attention relative to those in other neurodegenerative diseases. Such alterations to the BBB and BSCB have the potential to impact on CNS exposure of drugs in ALS, modulating the effectiveness of drugs intended to reach the brain and the toxicity of drugs that are not intended to reach the brain. Given the clinical importance of these phenomena, this review will summarise reported modifications to the BBB and BSCB in ALS, discuss their impact on CNS drug exposure and suggest further research directions so as to optimise medicine use in people with ALS.


Organoid ◽  
2021 ◽  
Vol 1 ◽  
pp. e10
Author(s):  
Hong Nam Kim

The blood-brain barrier (BBB) is a transport barrier that suppresses the translocation of potentially harmful substances to the brain tissue. Although the BBB is known to be associated with many kinds of neuropathology, such as neuroinflammation and neurodegenerative diseases, the conventionally used animal and Transwell models cannot provide sufficient information due to genetic and functional heterogeneity in comparison with humans and limited monitoring capabilities. Recently, human cell-based three-dimensional BBB models have been developed, and these models provide in vivo-like BBB structures and functions. In this review, we provide an overview of the recent advances in BBB models with a particular focus on the simulation of BBB-associated brain physiology and neuropathology. To this end, important factors for recapitulating the in vivo characteristics of the BBB are described. Furthermore, approaches to recapitulate the BBB physiology using engineering methods are summarized. The applications of BBB models in the study of neuropathology, such as inflammation and neurodegenerative diseases, are also presented.


2021 ◽  
Vol 22 (14) ◽  
pp. 7710
Author(s):  
Ying-Chieh Wu ◽  
Tuuli-Maria Sonninen ◽  
Sanni Peltonen ◽  
Jari Koistinaho ◽  
Šárka Lehtonen

The blood–brain barrier (BBB) regulates the delivery of oxygen and important nutrients to the brain through active and passive transport and prevents neurotoxins from entering the brain. It also has a clearance function and removes carbon dioxide and toxic metabolites from the central nervous system (CNS). Several drugs are unable to cross the BBB and enter the CNS, adding complexity to drug screens targeting brain disorders. A well-functioning BBB is essential for maintaining healthy brain tissue, and a malfunction of the BBB, linked to its permeability, results in toxins and immune cells entering the CNS. This impairment is associated with a variety of neurological diseases, including Alzheimer’s disease and Parkinson’s disease. Here, we summarize current knowledge about the BBB in neurodegenerative diseases. Furthermore, we focus on recent progress of using human-induced pluripotent stem cell (iPSC)-derived models to study the BBB. We review the potential of novel stem cell-based platforms in modeling the BBB and address advances and key challenges of using stem cell technology in modeling the human BBB. Finally, we highlight future directions in this area.


Author(s):  
Maria Suessmilch ◽  
Julie-Myrtille Bourgognon ◽  
Jonathan Cavanagh

Brain inflammation markers are present in several psychiatric and neurodegenerative disorders like major depressive disorder, Alzheimers disease and schizophrenia. Inflammation is also linked to sickness behaviour (social withdrawal, decreased appetite, impaired concentration, irritability), a mechanism by which the body redirects its resources to fight infection and encourage wound healing. The topical application of Aldara triggers systemic type I and II interferon and pro-inflammatory cytokine production, immune cell infiltration into the skin and hyperkeratosis and has been used as a model of psoriasis since 2009(1). We have recently reported that Imiquimod, the active component of Aldara, can enter the brain within 4 hours of topical application(2) and induces a transcriptional interferon and chemokine response in the brain, along with the infiltration of immune cells, a reduction in hippocampal neurogenesis and a reduction in burrowing behaviour(3). To allow us to understand the mechanisms of immune cell entry into the brain following topical Aldara treatment, we investigated blood brain barrier (BBB) integrity using a number of experimental techniques.


2006 ◽  
Vol 10 (2) ◽  
pp. 128-131 ◽  
Author(s):  
Dixon M. Moody

An intact blood-brain barrier and normal production, circulation, and absorption of cerebrospinal fluid are critical for normal brain function. Minor disruptions of barrier function are without clinical consequences. Major disruptions accompany most significant acute brain injuries. The anatomic location of the blood-brain barrier is the endothelial cells of arterioles, capillaries, veins, and the epithelial cell surface of the choroid plexus. However, endothelial cells require the presence of glial cells to maintain barrier function. During cardiopulmonary bypass, several factors may result in a temporary disruption of the barrier; the most important are systemic inflammatory response and focal ischemia due to emboli. Lacking a lymphatic system, the brain depends on the circulation of cerebrospinal fluid to remove the products of metabolism, and the circulation of cerebrospinal fluid depends on a vascular systolic pulse wave to drive this fluid antegrade along the brain paravascular spaces. Although it is not possible to identify this paravavscular space histologically, its presence is confirmed by tracer methods.


2018 ◽  
Vol 19 (12) ◽  
pp. 3818 ◽  
Author(s):  
Oxana Semyachkina-Glushkovskaya ◽  
Dmitry Postnov ◽  
Jürgen Kurths

The peripheral lymphatic system plays a crucial role in the recovery mechanisms after many pathological changes, such as infection, trauma, vascular, or metabolic diseases. The lymphatic clearance of different tissues from waste products, viruses, bacteria, and toxic proteins significantly contributes to the correspondent recovery processes. However, understanding of the cerebral lymphatic functions is a challenging problem. The exploration of mechanisms of lymphatic communication with brain fluids as well as the role of the lymphatic system in brain drainage, clearance, and recovery is still in its infancy. Here we review novel concepts on the anatomy and physiology of the lymphatics in the brain, which warrant a substantial revision of our knowledge about the role of lymphatics in the rehabilitation of the brain functions after neural pathologies. We discuss a new vision on the connective bridge between the opening of a blood–brain barrier and activation of the meningeal lymphatic clearance. The ability to stimulate the lymph flow in the brain, is likely to play an important role in developing future innovative strategies in neurorehabilitation therapy.


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