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Hussain B, Fang C, Chang J. Blood-Brain Barrier Breakdown: An Emerging Biomarker of Cognitive Impairment in Normal Aging and Dementia. Front Neurosci 2021; 15:688090. [PMID: 34489623 PMCID: PMC8418300 DOI: 10.3389/fnins.2021.688090] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
The blood–brain barrier (BBB) plays a vital role in maintaining the specialized microenvironment of the neural tissue. It separates the peripheral circulatory system from the brain parenchyma while facilitating communication. Alterations in the distinct physiological properties of the BBB lead to BBB breakdown associated with normal aging and various neurodegenerative diseases. In this review, we first briefly discuss the aging process, then review the phenotypes and mechanisms of BBB breakdown associated with normal aging that further cause neurodegeneration and cognitive impairments. We also summarize dementia such as Alzheimer's disease (AD) and vascular dementia (VaD) and subsequently discuss the phenotypes and mechanisms of BBB disruption in dementia correlated with cognition decline. Overlaps between AD and VaD are also discussed. Techniques that could identify biomarkers associated with BBB breakdown are briefly summarized. Finally, we concluded that BBB breakdown could be used as an emerging biomarker to assist to diagnose cognitive impairment associated with normal aging and dementia.
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Affiliation(s)
- Basharat Hussain
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cheng Fang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Junlei Chang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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Filippelli M, dell'Omo R, Gelso A, Rinaldi M, Bartollino S, Napolitano P, Russo A, Campagna G, Costagliola C. Effects of topical low-dose preservative-free hydrocortisone on intraocular pressure in patients affected by ocular surface disease with and without glaucoma. Graefes Arch Clin Exp Ophthalmol 2021; 260:247-253. [PMID: 34406502 DOI: 10.1007/s00417-021-05345-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 07/05/2021] [Accepted: 07/26/2021] [Indexed: 12/01/2022] Open
Abstract
PURPOSE This study aims to investigate the safety and efficacy of short-term treatment for ocular surface disease (OSD) with topical low-dose (1,005 mg) preservative-free hydrocortisone in one hundred patients with and without glaucoma. METHODS This was an open label non-randomized clinical trial. Patients with OSD with and without primary open-angle glaucoma (POAG) received topical low-dose (1,005 mg) preservative-free hydrocortisone twice daily in each eye for 2 weeks. All patients underwent a complete ophthalmological examination at baseline (T0) and at 1 (T1) and 2 (T2) weeks post-treatment. At each visit, the intraocular pressure (IOP) and the ocular surface disease index (OSDI) questionnaire scores were recorded; the Schirmer test was performed only at T0 and T2. RESULTS The OSDI score significantly decreased in both the POAG and no-POAG groups (both p < 0.0001) after hydrocortisone treatment, with no difference between the two groups (p = 0.72). There were no significant differences in IOP and Schirmer test results between T0 and T2 in both treatment groups (p = 0.68 and p = 0.83, respectively). CONCLUSIONS Topical low-dose (1,005 mg) preservative-free hydrocortisone is safe and effective for improving OSD symptoms both in patients with and without POAG. TRIAL REGISTRATION The trial was registered at clinicaltrials.gov under NCT04536129 on 01/09/2020 ("retrospectively registered").
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Affiliation(s)
- M Filippelli
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy.
| | - R dell'Omo
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - A Gelso
- "Villa Dei Fiori" Hospital, Acerra, Naples, Italy
| | - M Rinaldi
- Department of Ophthalmology, University Della Campania Luigi Vanvitelli, Naples, Italy
| | - S Bartollino
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - P Napolitano
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - A Russo
- "Villa Dei Fiori" Hospital, Acerra, Naples, Italy
| | - G Campagna
- Department of Medical-Surgical Sciences and Translational Medicine, University of Rome "La Sapienza", Rome, Italy
| | - C Costagliola
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
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Watanabe C, Imaizumi T, Kawai H, Suda K, Honma Y, Ichihashi M, Ema M, Mizutani KI. Aging of the Vascular System and Neural Diseases. Front Aging Neurosci 2020; 12:557384. [PMID: 33132896 PMCID: PMC7550630 DOI: 10.3389/fnagi.2020.557384] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/01/2020] [Indexed: 12/14/2022] Open
Abstract
Vertebrates have acquired complex high-order functions facilitated by the dispersion of vascular and neural networks to every corner of the body. Blood vessels deliver oxygen and nutrients to all cells and provide essential transport systems for removing waste products. For these functions, tissue vascularization must be spatiotemporally appropriate. Recent studies revealed that blood vessels create a tissue-specific niche, thus attracting attention as biologically active sites for tissue development. Each capillary network is critical for maintaining proper brain function because age-related and disease-related impairment of cognitive function is associated with the loss or diminishment of brain capillaries. This review article highlights how structural and functional alterations in the brain vessels may change with age and neurogenerative diseases. Capillaries are also responsible for filtering toxic byproducts, providing an appropriate vascular environment for neuronal function. Accumulation of amyloid β is a key event in Alzheimer’s disease pathogenesis. Recent studies have focused on associations reported between Alzheimer’s disease and vascular aging. Furthermore, the glymphatic system and meningeal lymphatic systems contribute to a functional unit for clearance of amyloid β from the brain from the central nervous system into the cervical lymph nodes. This review article will also focus on recent advances in stem cell therapies that aim at repopulation or regeneration of a degenerating vascular system for neural diseases.
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Affiliation(s)
- Chisato Watanabe
- Laboratory of Stem Cell Biology, Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe, Japan.,Department of Stem Cells and Human Disease Models, Research Center for Animal Life Science, Shiga University of Medical Science, Shiga, Japan
| | - Tsutomu Imaizumi
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., Osaka, Japan
| | - Hiromi Kawai
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., Osaka, Japan
| | - Kazuma Suda
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., Osaka, Japan
| | - Yoichi Honma
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., Osaka, Japan
| | - Masamitsu Ichihashi
- Laboratory of Stem Cell Biology, Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe, Japan
| | - Masatsugu Ema
- Department of Stem Cells and Human Disease Models, Research Center for Animal Life Science, Shiga University of Medical Science, Shiga, Japan.,Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University Institute for Advanced Study, Kyoto, Japan
| | - Ken-Ichi Mizutani
- Laboratory of Stem Cell Biology, Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe, Japan
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Apple DM, Kokovay E. Vascular niche contribution to age-associated neural stem cell dysfunction. Am J Physiol Heart Circ Physiol 2017; 313:H896-H902. [PMID: 28801522 PMCID: PMC5792207 DOI: 10.1152/ajpheart.00154.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/01/2017] [Accepted: 08/05/2017] [Indexed: 01/15/2023]
Abstract
Neural stem cells (NSCs) persist throughout life in the dentate gyrus and the ventricular-subventricular zone, where they continuously provide new neurons and some glia. These cells are found in specialized niches that regulate quiescence, activation, differentiation, and cell fate choice. A key aspect of the regulatory niche is the vascular plexus, which modulates NSC behavior during tissue homeostasis and regeneration. During aging, NSCs become depleted and dysfunctional, resulting in reduced neurogenesis and poor brain repair. In this review, we discuss the emerging evidence that changes in the vascular niche both structurally and functionally contribute to reduced neurogenesis during aging and how this might contribute to reduced plasticity and repair in the aged brain.
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Affiliation(s)
| | - Erzsebet Kokovay
- Department of Cell Systems and Anatomy, Barshop Institute for Aging and Longevity Studies, UT Health San Antonio, San Anontio, Texas
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Affiliation(s)
- Hassan Ghasemi
- Department of Ophthalmology, Shahed University, Tehran, Iran
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Peptidoglycan and muramyl dipeptide from Staphylococcus aureus induce the expression of VEGF-A in human limbal fibroblasts with the participation of TLR2-NFκB and NOD2-EGFR. Graefes Arch Clin Exp Ophthalmol 2012; 251:53-62. [DOI: 10.1007/s00417-012-2130-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 07/24/2012] [Accepted: 07/29/2012] [Indexed: 12/14/2022] Open
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Abstract
The ocular surface is the first line of defence in the eye against environmental microbes. The ocular innate immune system consists of a combination of anatomical, mechanical and immunological defence mechanisms. TLRs (Toll-like receptors), widely expressed by the ocular surface, are able to recognize microbial pathogens and to trigger the earliest immune response leading to inflammation. Increasing evidence highlights the crucial role of TLRs in regulating innate immune responses during ocular surface infective and non-infective inflammatory conditions. In addition, recent observations have shown that TLRs modulate the adaptive immune response, also playing an important role in ocular autoimmune and allergic diseases. One of the main goals of ocular surface treatment is to control the inflammatory reaction in order to preserve corneal integrity and transparency. Recent experimental evidence has shown that specific modulation of TLR pathways induces an improvement in several ocular inflammatory conditions, such as allergic conjunctivitis, suggesting new therapeutic anti-inflammatory strategies. The purpose of the present review is to summarize the current knowledge of TLRs at the ocular surface and to propose them as potential targets of therapy for ocular inflammatory conditions.
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Redfern RL, Reins RY, McDermott AM. Toll-like receptor activation modulates antimicrobial peptide expression by ocular surface cells. Exp Eye Res 2010; 92:209-20. [PMID: 21195713 DOI: 10.1016/j.exer.2010.12.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/19/2010] [Accepted: 12/06/2010] [Indexed: 01/08/2023]
Abstract
The ability of the ocular surface to respond to pathogens is in part attributed to toll-like receptors (TLRs) that recognize conserved motifs on various microbes. This study examines TLR expression on various ocular surface cells, if TLR agonists can modulate the expression of antimicrobial peptides (AMPs), human beta defensins (hBD) and cathelicidin (hCAP-18/LL-37) which maybe functionally active against Pseudomonas aeruginosa (PA) and if TLR agonists or AMPs can modulate TLR mRNA expression. TLR1-10 mRNA expression was examined in corneal epithelial, corneal stromal cells and conjunctival epithelial cells by RT-PCR. To confirm protein expression flow cytometry or immunostaining was performed for selected TLRs on some cell cultures. Ocular surface cells were cultured with a range of TLR agonists and then hBD-1, 2, 3, or hCAP-18 mRNA and protein expression was determined by RT-PCR and immunoblotting. In some experiments, cells were cultured with a cocktail of agonists for TLR3, 5 and 6/2 and the antimicrobial activity of the culture media was tested against PA. TLR mRNA expression was also examined in primary human corneal epithelial cells (HCEC) treated with either 3 μg/ml of hBD-2, 5 μg/ml of LL-37 or TLR4, 5 and 9 agonists. Overall, the ocular surface cells expressed mRNA for most of the TLRs but some differences were found. TLR2 was not detected in corneal fibroblasts, TLR4 was not detected in primary cultured or freshly isolated HCEC, TLR5 was not detected in conjunctival epithelial cells (IOBA-NHC) and corneal fibroblasts, TLR7 was not detected in freshly isolated HCEC and TLR10 was not detected in HCEC and IOBA-NHC. TLR8 mRNA was not expressed by any of the samples tested. Immunostaining of cadaver corneas revealed TLR5 and 9 expression throughout the cornea while TLR3 was significantly expressed only in the epithelium. Flow cytometry and immunostaining revealed cultured fibroblasts expressed TLR9 but had no significant TLR3 expression. hBD-2 expression was upregulated by TLR1/2, 3, 4, 5 and 6/2 agonists depending on the cell type, whereas only the TLR3 agonist upregulated the expression of hCAP-18 in primary HCEC. The combination of TLR3, 5 and 6/2 agonists in primary HCEC, upregulated hBD-2 and hCAP-18 mRNA and peptide expression and secretion into the culture media, which significantly killed PA. This antimicrobial activity was primarily attributed to LL-37. TLR agonists did not modulate TLR expression itself, however, LL-37 or hBD-2 downregulated TLR5, 7 and/or 9 mRNA depending on the cell type. TLRs are expressed on the ocular surface and TLR agonists trigger the production of LL-37 and hBD-2, with LL-37 being particularly important for protecting the ocular surface against PA infection.
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Affiliation(s)
- Rachel L Redfern
- University of Houston, College of Optometry, 505 J. Davis Armistead Building, 4901 Calhoun Road, Houston, TX 77204-2020, USA
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