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Moiseenok AG, Kanunnikova NP. Brain CoA and Acetyl CoA Metabolism in Mechanisms of Neurodegeneration. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:466-480. [PMID: 37080933 DOI: 10.1134/s000629792304003x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
The processes of biotransformation of pantothenic acid (Pan) in the biosynthesis and hydrolysis of CoA, key role of pantothenate kinase (PANK) and CoA synthetase (CoASY) in the formation of the priority mitochondrial pool of CoA, with a high metabolic turnover of the coenzyme and limited transport of Pan across the blood-brain barrier are considered. The system of acetyl-CoA, a secondary messenger, which is the main substrate of acetylation processes including formation of N-acetyl aspartate and acetylcholine, post-translational modification of histones, predetermines protection of the neurons against degenerative signals and cholinergic neurotransmission. Biochemical mechanisms of neurodegenerative syndromes in the cases of PANK and CoASY defects, and the possibility of correcting of CoA biosynthesis in the models with knockouts of these enzymes have been described. The data of a post-mortem study of the brains from the patients with Huntington's and Alzheimer's diseases are presented, proving Pan deficiency in the CNS, which is especially pronounced in the pathognomonic neurostructures. In the frontal cortex of the patients with Parkinson's disease, combined immunofluorescence of anti-CoA- and anti-tau protein was detected, reflecting CoAlation during dimerization of the tau protein and its redox sensitivity. Redox activity and antioxidant properties of the precursors of CoA biosynthesis were confirmed in vitro with synaptosomal membranes and mitochondria during modeling of aluminum neurotoxicity accompanied by the decrease in the level of CoA in CNS. The ability of CoA biosynthesis precursors to stabilize glutathione pool in neurostructures, in particular, in the hippocampus, is considered as a pathogenetic protection mechanism during exposure to neurotoxins, development of neuroinflammation and neurodegeneration, and justifies the combined use of Pan derivatives (for example, D-panthenol) and glutathione precursors (N-acetylcysteine). Taking into account the discovery of new functions of CoA (redox-dependent processes of CoAlation of proteins, possible association of oxidative stress and deficiency of Pan (CoA) in neurodegenerative pathology), it seems promising to study bioavailability and biotransformation of Pan derivatives, in particular of D-panthenol, 4'-phospho-pantetheine, its acylated derivatives, and compositions with redox pharmacological compounds, are promising for their potential use as etiopathogenetic agents.
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Affiliation(s)
- Andrey G Moiseenok
- Institute of Biochemistry of Biologically Active Substances, National Academy of Sciences of Belarus, Grodno, 230023, Belarus.
| | - Nina P Kanunnikova
- Institute of Biochemistry of Biologically Active Substances, National Academy of Sciences of Belarus, Grodno, 230023, Belarus
- Yanka Kupala's Grodno State University, Grodno, 230023, Belarus
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2
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A Historical Review of Brain Drug Delivery. Pharmaceutics 2022; 14:pharmaceutics14061283. [PMID: 35745855 PMCID: PMC9229021 DOI: 10.3390/pharmaceutics14061283] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.
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Moretti R, Peinkhofer C. B Vitamins and Fatty Acids: What Do They Share with Small Vessel Disease-Related Dementia? Int J Mol Sci 2019; 20:E5797. [PMID: 31752183 PMCID: PMC6888477 DOI: 10.3390/ijms20225797] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/21/2019] [Accepted: 11/12/2019] [Indexed: 12/12/2022] Open
Abstract
Many studies have been written on vitamin supplementation, fatty acid, and dementia, but results are still under debate, and no definite conclusion has yet been drawn. Nevertheless, a significant amount of lab evidence confirms that vitamins of the B group are tightly related to gene control for endothelium protection, act as antioxidants, play a co-enzymatic role in the most critical biochemical reactions inside the brain, and cooperate with many other elements, such as choline, for the synthesis of polyunsaturated phosphatidylcholine, through S-adenosyl-methionine (SAM) methyl donation. B-vitamins have anti-inflammatory properties and act in protective roles against neurodegenerative mechanisms, for example, through modulation of the glutamate currents and a reduction of the calcium currents. In addition, they also have extraordinary antioxidant properties. However, laboratory data are far from clinical practice. Many studies have tried to apply these results in everyday clinical activity, but results have been discouraging and far from a possible resolution of the associated mysteries, like those represented by Alzheimer's disease (AD) or small vessel disease dementia. Above all, two significant problems emerge from the research: No consensus exists on general diagnostic criteria-MCI or AD? Which diagnostic criteria should be applied for small vessel disease-related dementia? In addition, no general schema exists for determining a possible correct time of implementation to have effective results. Here we present an up-to-date review of the literature on such topics, shedding some light on the possible interaction of vitamins and phosphatidylcholine, and their role in brain metabolism and catabolism. Further studies should take into account all of these questions, with well-designed and world-homogeneous trials.
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Affiliation(s)
- Rita Moretti
- Neurology Clinic, Department of Medical, Surgical and Health Sciences, University of Trieste, 34149 Trieste, Italy;
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Patassini S, Begley P, Xu J, Church SJ, Kureishy N, Reid SJ, Waldvogel HJ, Faull RLM, Snell RG, Unwin RD, Cooper GJS. Cerebral Vitamin B5 (D-Pantothenic Acid) Deficiency as a Potential Cause of Metabolic Perturbation and Neurodegeneration in Huntington's Disease. Metabolites 2019; 9:E113. [PMID: 31212603 PMCID: PMC6630497 DOI: 10.3390/metabo9060113] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 05/31/2019] [Accepted: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an expanded CAG repeat in exon 1 of the HTT gene. HD usually manifests in mid-life with loss of GABAergic projection neurons from the striatum accompanied by progressive atrophy of the putamen followed by other brain regions, but linkages between the genetics and neurodegeneration are not understood. We measured metabolic perturbations in HD-human brain in a case-control study, identifying pervasive lowering of vitamin B5, the obligatory precursor of coenzyme A (CoA) that is essential for normal intermediary metabolism. Cerebral pantothenate deficiency is a newly-identified metabolic defect in human HD that could potentially: (i) impair neuronal CoA biosynthesis; (ii) stimulate polyol-pathway activity; (iii) impair glycolysis and tricarboxylic acid cycle activity; and (iv) modify brain-urea metabolism. Pantothenate deficiency could lead to neurodegeneration/dementia in HD that might be preventable by treatment with vitamin B5.
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Affiliation(s)
- Stefano Patassini
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand.
- Owlstone Medical, Cambridge Science Park, Cambridge CB4 0GJ, UK.
| | - Paul Begley
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
| | - Jingshu Xu
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
- Manchester Cancer Research Centre Building, The University of Manchester, Manchester M20 4GJ, UK.
| | - Stephanie J Church
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
| | - Nina Kureishy
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
| | - Suzanne J Reid
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand.
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand.
| | - Richard L M Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand.
| | - Russell G Snell
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand.
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1142, New Zealand.
| | - Richard D Unwin
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
| | - Garth J S Cooper
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M19 9NT, UK.
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand.
- Manchester Cancer Research Centre Building, The University of Manchester, Manchester M20 4GJ, UK.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland 1142, New Zealand.
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Di Marco A, Gonzalez Paz O, Fini I, Vignone D, Cellucci A, Battista MR, Auciello G, Orsatti L, Zini M, Monteagudo E, Khetarpal V, Rose M, Dominguez C, Herbst T, Toledo-Sherman L, Summa V, Muñoz-Sanjuán I. Application of an in Vitro Blood–Brain Barrier Model in the Selection of Experimental Drug Candidates for the Treatment of Huntington’s Disease. Mol Pharm 2019; 16:2069-2082. [DOI: 10.1021/acs.molpharmaceut.9b00042] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Vinod Khetarpal
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
| | - Mark Rose
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
| | - Celia Dominguez
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
| | - Todd Herbst
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
| | - Leticia Toledo-Sherman
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
| | | | - Ignacio Muñoz-Sanjuán
- CHDI Management, CHDI Foundation, Center Drive Los Angeles 6080, California, United States
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Uchida Y, Ito K, Ohtsuki S, Kubo Y, Suzuki T, Terasaki T. Major involvement of Na(+) -dependent multivitamin transporter (SLC5A6/SMVT) in uptake of biotin and pantothenic acid by human brain capillary endothelial cells. J Neurochem 2015; 134:97-112. [PMID: 25809983 DOI: 10.1111/jnc.13092] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 03/08/2015] [Accepted: 03/09/2015] [Indexed: 12/24/2022]
Abstract
The purpose of this study was to clarify the expression of Na(+) -dependent multivitamin transporter (SLC5A6/SMVT) and its contribution to the supply of biotin and pantothenic acid to the human brain via the blood-brain barrier. DNA microarray and immunohistochemical analyses confirmed that SLC5A6 is expressed in microvessels of human brain. The absolute expression levels of SLC5A6 protein in isolated human and monkey brain microvessels were 1.19 and 0.597 fmol/μg protein, respectively, as determined by a quantitative targeted absolute proteomics technique. Using an antibody-free method established by Kubo et al. (2015), we found that SLC5A6 was preferentially localized at the luminal membrane of brain capillary endothelium. Knock-down analysis using SLC5A6 siRNA showed that SLC5A6 accounts for 88.7% and 98.6% of total [(3) H]biotin and [(3) H]pantothenic acid uptakes, respectively, by human cerebral microvascular endothelial cell line hCMEC/D3. SLC5A6-mediated transport in hCMEC/D3 was markedly inhibited not only by biotin and pantothenic acid, but also by prostaglandin E2, lipoic acid, docosahexaenoic acid, indomethacin, ketoprofen, diclofenac, ibuprofen, phenylbutazone, and flurbiprofen. This study is the first to confirm expression of SLC5A6 in human brain microvessels and to provide evidence that SLC5A6 is a major contributor to luminal uptake of biotin and pantothenic acid at the human blood-brain barrier. In humans, it was unclear (not concluded) about what transport system at the blood-brain barrier (BBB) is responsible for the brain uptakes of two vitamins, biotin and pantothenic acid, which are necessary for brain proper function. This study clarified for the first time that the solute carrier 5A6/Na(+) -dependent multivitamin transporter SLC5A6/SMVT is responsible for the supplies of biotin and pantothenic acid into brain across the BBB in humans. DHA, docosahexaenoic acid; NSAID, non-steroidal anti-inflammatory drug; PGE2, prostaglandin E2.
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Affiliation(s)
- Yasuo Uchida
- Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
| | - Katsuaki Ito
- Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
| | - Sumio Ohtsuki
- Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yoshiyuki Kubo
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Takashi Suzuki
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Tetsuya Terasaki
- Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
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7
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Moiseenok AG, Katkovskaya IN, Gurinovich VA, Denisov AA, Pashkevich SG, Kul’chitskii VA. Absorption and biotransformation of the coenzyme A precursor D-pantethine in rat hippocampus. NEUROCHEM J+ 2010. [DOI: 10.1134/s1819712410040033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Moiseenok AG, Gurinovich VA, Yevkovich IN, Badun GA, Tyasto ZA, Stepanichev MY, Lazareva NA, Onufriev MV, Gulyaeva NV. Synthesis of 4′-[3H]-Phospho-pantothenic acid and studies of its metabolism in structures of the brain. NEUROCHEM J+ 2007. [DOI: 10.1134/s181971240704006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Spector R, Johanson CE. REVIEW: Vitamin transport and homeostasis in mammalian brain: focus on Vitamins B and E. J Neurochem 2007; 103:425-38. [PMID: 17645457 DOI: 10.1111/j.1471-4159.2007.04773.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the application of genetic and molecular biology techniques, there has been substantial progress in understanding how vitamins are transferred across the mammalian blood-brain barrier and choroid plexus into brain and CSF and how vitamin homeostasis in brain is achieved. In most cases (with the exception of the sodium-dependent multivitamin transporter for biotin, pantothenic acid, and lipoic acid), the vitamins are transported by separate carriers through the blood-brain barrier or choroid plexus. Then the vitamins are accumulated by brain cells by separate, specialized systems. This review focuses on six vitamins (B(1), B(3), B(6), pantothenic acid, biotin, and E) and the newer genetic information including relevant 'knockdown' or 'knockout' models in mice and humans. The overall objective is to integrate this newer information with previous physiological and biochemical observations to achieve a better understanding of vitamin transport and homeostasis in brain. This is especially important in view of the newly described non-cofactor vitamin roles in brain (e.g. of B(1), B(3), B(6), and E) and the potential roles of vitamins in the therapy of brain disorders.
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Affiliation(s)
- Reynold Spector
- Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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Suzuki T, Oshimi M, Tomono K, Hanano M, Watanabe J. Investigation of transport mechanism of pentazocine across the blood-brain barrier using the in situ rat brain perfusion technique. J Pharm Sci 2002; 91:2346-53. [PMID: 12379919 DOI: 10.1002/jps.10224] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
To characterize pentazocine (PTZ) transport across the blood-brain barrier (BBB), the cerebrovascular permeability-surface area product (PS(inf)) of PTZ was determined by a well-established in situ rat brain perfusion technique. The uptake kinetics of PTZ by the rat brain exhibited saturability, which indicates the simultaneous mechanisms of carrier-mediated transport and passive diffusion. The kinetic parameters were estimated as follows: maximal influx rate (V(max)), 27.2 +/- 5.2 nmol/s/g brain; apparent Michaelis constant (K(m)) for the saturable component of PTZ uptake, 2.9 +/- 0.5 mM; nonsaturable uptake rate constant (K(d)), 1.5 +/- 0.3 microL/s/g brain. BBB transport of PTZ was significantly inhibited by cationic drugs such as diphenhydramine, propranolol, and eptazocine (a narcotic-antagonist analgesic), but not by choline, suggesting that the PTZ transport system is shared by cationic drugs. Furthermore, co-perfusion of verapamil caused a significant (two-fold) increase in the BBB permeability to PTZ. This finding indicates that PTZ may be a substrate of the endogenous BBB efflux transport system, P-glycoprotein. These findings demonstrate that the primary mechanism governing the uptake of PTZ by the brain is carrier-mediated transport, not passive diffusion.
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Affiliation(s)
- Toyofumi Suzuki
- Department of Pharmaceutics, College of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi-shi, Chiba 274-8555, Japan.
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Smith QR. Brain perfusion systems for studies of drug uptake and metabolism in the central nervous system. PHARMACEUTICAL BIOTECHNOLOGY 1996; 8:285-307. [PMID: 8791815 DOI: 10.1007/978-1-4899-1863-5_15] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Q R Smith
- Neurochemistry and Brain Transport Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA
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12
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Alberghina M, Lupo G, Anfuso CD, Moro F. Palmitate transport through the blood-retina and blood-brain barrier of rat visual system during aging. Neurosci Lett 1993; 150:17-20. [PMID: 8469396 DOI: 10.1016/0304-3940(93)90097-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The permeability-surface area product (PA) of [1-14C]palmitate at the blood-retina (BRB) and blood-brain barrier (BBB) was determined after short carotid perfusion in male Sprague-Dawley rats at 4, 14 and 28 months of age. For the retina, optic nerve and tract, lateral geniculate body, visual and parietal cortex, there was no significant difference among mean PAs in any age group. For superior colliculus, frontal cortex, striatum, hippocampus and olfactory bulb, a slight but significant increase of PA values was observed between young (4-month-old) and senescent (28-month-old) rats. Our results indicate that aging does not affect influx into retina and other structures of rat visual system of the palmitate, a metabolic substrate for which carrier-mediated transport across the BRB and BBB has not been demonstrated.
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Affiliation(s)
- M Alberghina
- Institute of Biochemistry, Faculty of Medicine, University of Catania, Italy
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Shi F, Bailey C, Malick AW, Audus KL. Biotin uptake and transport across bovine brain microvessel endothelial cell monolayers. Pharm Res 1993; 10:282-8. [PMID: 8456078 DOI: 10.1023/a:1018903330985] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Primary cultures of bovine brain microvessel endothelial cells (BMECs) were used to characterize blood-brain barrier (BBB) uptake and transport of biotin. Both the uptake and the transcellular transport of either radiolabeled or fluorescein-conjugated biotin by confluent monolayers of BMECs were measured. Biotin uptake (Km = 123 microM) and bidirectional transport across BMEC monolayers was a saturable process and could be competed for by unlabeled biotin, biocytin, and biotinmethyl ester. Pantothenic and nonanoic acid were found not to be effective competitors for either biotin uptake or transport. The metabolic inhibitor, 2-deoxyglucose, had only small effects on the saturable apical-to-basolateral transport and apical uptake of biotin by BMECs. In contrast, basolateral-to-apical transport of biotin was substantially attenuated by 2-deoxyglucose pretreatment. Results supported the existence of specific and saturable uptake and efflux carrier systems for biotin in BMEC monolayers. The function of these systems was dependent to some degree on the metabolic status of the BMECs. Our findings confirm the existence of a biotin uptake system at the BBB in vivo and provide the first indication of an efflux system for biotin in BMECs.
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Affiliation(s)
- F Shi
- Department of Pharmaceutical Chemistry, University of Kansas, School of Pharmacy, Lawrence 66045-2504
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Leinweber FJ. Drug disposition in the mammalian eye and brain: a comparison of mechanisms. Drug Metab Rev 1991; 23:133-246. [PMID: 1868775 DOI: 10.3109/03602539109029758] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- F J Leinweber
- Department of Drug Metabolism, Hoffmann-La Roche, Nutley, New Jersey 07110
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15
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Affiliation(s)
- R Spector
- Merck Sharp & Dohme Research Laboratories, Rahway, NJ 07065
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Abstract
The unidirectional transport of [3H]myo-inositol across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured using an in situ rat brain perfusion technique. Myo-inositol was transported across the blood-brain barrier by a low capacity, saturable system with a one-half saturation concentration of approximately 0.1 mM. The permeability surface-area product was 6.2 x 10(-5) S-1 with a myo-inositol concentration of 0.02 mM in the perfusate. The myo-inositol stereoisomer scyllo-inositol but not (+)-chiro-inositol (both 1 mM) inhibited myo-inositol transfer through the blood-brain barrier. These observations provide evidence that myo-inositol is transferred through the blood-brain barrier by simple diffusion and a stereospecific, saturable transport system.
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Affiliation(s)
- R Spector
- Department of Internal Medicine, University of Iowa, College of Medicine, Iowa City 52242
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Abstract
The mechanisms by which biotin enters and leaves brain, choroid plexus and cerebrospinal fluid (CSF) were investigated by injecting [3H]biotin either intravenously or intraventricularly into adult rabbits. [3H] biotin, either alone or together with unlabeled biotin was infused at a constant rate into conscious rabbits. At 180 minutes, [3H]biotin had entered CSF, choroid plexus, and brain. In brain, CSF, and plasma, greater than 90% of the nonvolatile 3H was associated with [3H]biotin. The addition of 400 mumol/kg unlabeled biotin to the infusion syringe decreased the penetration of [3H]biotin into brain and CSF by approximately 70 percent. Two hours after an intraventricular injection, [3H]biotin was cleared from the CSF more rapidly than mannitol and minimal metabolism of the [3H]biotin had occurred in brain. However, 18 hours after an intraventricular injection, approximately 35% of the [3H]biotin remaining in brain had been covalently incorporated into proteins, presumably into carboxylase apoenzymes. These results show that biotin enters CSF and brain by saturable transport systems that do not depend on metabolism of the biotin. However, [3H]biotin is very slowly incorporated covalently into proteins in brain in vivo.
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Affiliation(s)
- R Spector
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242
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Abstract
Across the cerebral capillaries, the anatomical locus of the blood-brain barrier, the unidirectional influxes of the saturated fatty acids, octanoic and myristic acids, and the unsaturated essential fatty acid, linoleic acid, were measured. Employing an in situ rat brain perfusion technique that allows control of perfusate composition and accurate measurement of perfusate-to-brain fatty acid transport, we found that both [14C]octanoic and [14C]myristic acids were transported through the blood-brain barrier in vivo, in large part, by a specific, probenecid-sensitive transport system. However, the transport of [14C]linoleic acid was not probenecid sensitive. With 0.5 microM fatty acid but no plasma proteins in the perfusate, the permeability-surface area constant was higher for myristic acid (4.8 X 10(-2) X s-1) than for octanoic and linoleic acids (1.5 and 1.2 X 10(-2) X s-1, respectively). Approximately 70, 30, and 25% of the [14C]myristic, [14C]octanoic, or [14C]linoleic acids, respectively, were extracted from the perfusate.
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Affiliation(s)
- R Spector
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City
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Abstract
The unidirectional influx of hypoxanthine across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured with an in situ rat brain perfusion technique employing [3H]hypoxanthine. Hypoxanthine was transported across the blood-brain barrier by a saturable system with a one-half saturation concentration of approximately 0.4 mM. The permeability-surface area product was 3 X 10(-4) sec-1 with a hypoxanthine concentration of 0.02 microM in the perfusate. Adenine (4 mM) and uracil and theophylline (both 10 mM), but not inosine (10 mM) or leucine (1 mM), inhibited hypoxanthine transfer through the blood-brain barrier. Thus, hypoxanthine is transported through the blood-brain barrier by a high-capacity, saturable transport system with a half-saturation concentration about 100 times the plasma hypoxanthine concentration. Although involved in the transport hypoxanthine from blood into brain, this system is not powerful enough to transfer important quantities of hypoxanthine from blood into brain.
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Affiliation(s)
- R Spector
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242
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Abstract
The transport metabolism of [3H]quinolinic acid in the central nervous system of rabbits and rats were studied. In vitro [3H]quinolinic acid was not readily accumulated by isolated choroid plexus. After the intraventricular injection of tracer quantities of [3H]quinolinic acid, the [3H]quinolinic acid did not enter the brain as readily as concurrently injected [14C]mannitol and was not metabolized. The permeability-surface area constant for [3H]quinolinic acid at the rat blood-brain barrier was 1.5 +/- 1.3 X 10(-5) sec-1 compared to 2.8 +/- 0.4 X 10(-5) sec-1 for [3H]mannitol. Our results suggest that: 1) [3H]quinolinic acid is transported in the CNS by passive diffusion and 2) is not metabolized.
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21
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Abstract
The unidirectional influx of biotin across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured with an in situ rat brain perfusion technique employing [3H]biotin. Biotin was transported across the blood-brain barrier by a saturable system with a one-half saturation concentration of approximately 100 microM. The permeability-surface area products were 10(-4) s-1 with a biotin concentration of 0.02 microM in the perfusate. Probenecid, pantothenic acid, and nonanoic acid but not biocytin or biotin methylester (all 250 microM) inhibited biotin transfer through the blood-brain barrier. The isolated rabbit choroid plexus was unable to concentrate [3H]biotin from medium containing 1 nM [3H]biotin. These observations provide evidence that: biotin is transported through the blood-brain barrier by a saturable transport system that depends on a free carboxylic acid group, and the choroid plexus is probably not involved in the transfer of biotin between blood and cerebrospinal fluid.
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22
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Abstract
The unidirectional influx of niacinamide across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured with an in situ rat brain perfusion technique employing [14C]niacinamide. Niacinamide was transported rapidly across the blood-brain barrier by a system that was not saturable with 10 mM niacinamide in the perfusate. However, with periods of perfusion longer than 30 seconds, there was substantial backflow of [14C]niacinamide into the perfusate. Niacinamide (1.7 microM) transport through the blood-brain barrier was not significantly inhibited by 3-acetylpyridine. Thus, niacinamide is transported rapidly and bidirectionally through the blood-brain barrier by a high capacity transport system. Although involved in the transfer of niacinamide between blood and brain, this transport system does not play an important regulatory role in the synthesis of NMN, NAD, and NADP from niacinamide in brain.
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