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Antoniac I, Manescu (Paltanea) V, Paltanea G, Antoniac A, Nemoianu IV, Petrescu MI, Dura H, Bodog AD. Additive Manufactured Magnesium-Based Scaffolds for Tissue Engineering. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8693. [PMID: 36500191 PMCID: PMC9739563 DOI: 10.3390/ma15238693] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/01/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Additive manufacturing (AM) is an important technology that led to a high evolution in the manufacture of personalized implants adapted to the anatomical requirements of patients. Due to a worldwide graft shortage, synthetic scaffolds must be developed. Regarding this aspect, biodegradable materials such as magnesium and its alloys are a possible solution because the second surgery for implant removal is eliminated. Magnesium (Mg) exhibits mechanical properties, which are similar to human bone, biodegradability in human fluids, high biocompatibility, and increased ability to stimulate new bone formation. A current research trend consists of Mg-based scaffold design and manufacture using AM technologies. This review presents the importance of biodegradable implants in treating bone defects, the most used AM methods to produce Mg scaffolds based on powder metallurgy, AM-manufactured implants properties, and in vitro and in vivo analysis. Scaffold properties such as biodegradation, densification, mechanical properties, microstructure, and biocompatibility are presented with examples extracted from the recent literature. The challenges for AM-produced Mg implants by taking into account the available literature are also discussed.
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Affiliation(s)
- Iulian Antoniac
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
- Academy of Romanian Scientists, 54 Splaiul Independentei, 050094 Bucharest, Romania
| | - Veronica Manescu (Paltanea)
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
- Faculty of Electrical Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
| | - Gheorghe Paltanea
- Faculty of Electrical Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
| | - Aurora Antoniac
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
| | - Iosif Vasile Nemoianu
- Faculty of Electrical Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
| | - Mircea Ionut Petrescu
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania
| | - Horatiu Dura
- Faculty of Medicine, Lucian Blaga University of Sibiu, 550169 Sibiu, Romania
| | - Alin Danut Bodog
- Faculty of Medicine and Pharmacy, University of Oradea, 10 P-ta 1 December Street, 410073 Oradea, Romania
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2
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Maeoka Y, McCormick JA. NaCl cotransporter activity and Mg 2+ handling by the distal convoluted tubule. Am J Physiol Renal Physiol 2020; 319:F1043-F1053. [PMID: 33135481 DOI: 10.1152/ajprenal.00463.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The genetic disease Gitelman syndrome, knockout mice, and pharmacological blockade with thiazide diuretics have revealed that reduced activity of the NaCl cotransporter (NCC) promotes renal Mg2+ wasting. NCC is expressed along the distal convoluted tubule (DCT), and its activity determines Mg2+ entry into DCT cells through transient receptor potential channel subfamily M member 6 (TRPM6). Several other genetic forms of hypomagnesemia lower the drive for Mg2+ entry by inhibiting activity of basolateral Na+-K+-ATPase, and reduced NCC activity may do the same. Lower intracellular Mg2+ may promote further Mg2+ loss by directly decreasing activity of Na+-K+-ATPase. Lower intracellular Mg2+ may also lower Na+-K+-ATPase indirectly by downregulating NCC. Lower NCC activity also induces atrophy of DCT cells, decreasing the available number of TRPM6 channels. Conversely, a mouse model with increased NCC activity was recently shown to display normal Mg2+ handling. Moreover, recent studies have identified calcineurin and uromodulin (UMOD) as regulators of both NCC and Mg2+ handling by the DCT. Calcineurin inhibitors paradoxically cause hypomagnesemia in a state of NCC activation, but this may be related to direct effects on TRPM6 gene expression. In Umod-/- mice, the cause of hypomagnesemia may be partly due to both decreased NCC expression and lower TRPM6 expression on the cell surface. This mini-review discusses these new findings and the possible role of altered Na+ flux through NCC and ultimately Na+-K+-ATPase in Mg2+ reabsorption by the DCT.
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Affiliation(s)
- Yujiro Maeoka
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - James A McCormick
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
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3
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Ferdaus MZ, Mukherjee A, Nelson JW, Blatt PJ, Miller LN, Terker AS, Staub O, Lin DH, McCormick JA. Mg 2+ restriction downregulates NCC through NEDD4-2 and prevents its activation by hypokalemia. Am J Physiol Renal Physiol 2019; 317:F825-F838. [PMID: 31364380 PMCID: PMC6843039 DOI: 10.1152/ajprenal.00216.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hypomagnesemia is associated with reduced kidney function and life-threatening complications and sustains hypokalemia. The distal convoluted tubule (DCT) determines final urinary Mg2+ excretion and, via activity of the Na+-Cl- cotransporter (NCC), also plays a key role in K+ homeostasis by metering Na+ delivery to distal segments. Little is known about the mechanisms by which plasma Mg2+ concentration regulates NCC activity and how low-plasma Mg2+ concentration and K+ concentration interact to modulate NCC activity. To address this, we performed dietary manipulation studies in mice. Compared with normal diet, abundances of total NCC and phosphorylated NCC (pNCC) were lower after short-term (3 days) or long-term (14 days) dietary Mg2+ restriction. Altered NCC activation is unlikely to play a role, since we also observed lower total NCC abundance in mice lacking the two NCC-activating kinases, STE20/SPS-1-related proline/alanine-rich kinase and oxidative stress response kinase-1, after Mg2+ restriction. The E3 ubiquitin-protein ligase NEDD4-2 regulates NCC abundance during dietary NaCl loading or K+ restriction. Mg2+ restriction did not lower total NCC abundance in inducible nephron-specific neuronal precursor cell developmentally downregulated 4-2 (NEDD4-2) knockout mice. Total NCC and pNCC abundances were similar after short-term Mg2+ or combined Mg2+-K+ restriction but were dramatically lower compared with a low-K+ diet. Therefore, sustained NCC downregulation may serve a mechanism that enhances distal Na+ delivery during states of hypomagnesemia, maintaining hypokalemia. Similar results were obtained with long-term Mg2+-K+ restriction, but, surprisingly, NCC was not activated after long-term K+ restriction despite lower plasma K+ concentration, suggesting significant differences in distal tubule adaptation to acute or chronic K+ restriction.
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Affiliation(s)
- Mohammed Z. Ferdaus
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Anindit Mukherjee
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jonathan W. Nelson
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Philip J. Blatt
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Lauren N. Miller
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Andrew S. Terker
- 2Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Olivier Staub
- 3Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Dao-Hong Lin
- 4Department of Pharmacology, New York Medical College, Valhalla, New York
| | - James A. McCormick
- 1Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
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Pulikkathodi AK, Sarangadharan I, Chen YH, Lee GY, Chyi JI, Lee GB, Wang YL. Dynamic monitoring of transmembrane potential changes: a study of ion channels using an electrical double layer-gated FET biosensor. LAB ON A CHIP 2018; 18:1047-1056. [PMID: 29488525 DOI: 10.1039/c7lc01305a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this research, we have designed, fabricated and characterized an electrical double layer (EDL)-gated AlGaN/GaN high electron mobility transistor (HEMT) biosensor array to study the transmembrane potential changes of cells. The sensor array platform is designed to detect and count circulating tumor cells (CTCs) of colorectal cancer (CRC) and investigate cellular bioelectric signals. Using the EDL FET biosensor platform, cellular responses can be studied in physiological salt concentrations, thereby eliminating complex automation. Upon investigation, we discovered that our sensor response follows the transmembrane potential changes of captured cells. Our whole cell sensor platform can be used to monitor the dynamic changes in the membrane potential of cells. The effects of continuously changing electrolyte ion concentrations and ion channel blocking using cadmium are investigated. This methodology has the potential to be used as an electrophysiological probe for studying ion channel gating and the interaction of biomolecules in cells. The sensor can also be a point-of-care diagnostic tool for rapid screening of diseases.
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Affiliation(s)
- Anil Kumar Pulikkathodi
- Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan 300, R.O.C.
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5
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Porous magnesium-based scaffolds for tissue engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 71:1253-1266. [DOI: 10.1016/j.msec.2016.11.027] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/04/2016] [Accepted: 11/07/2016] [Indexed: 12/14/2022]
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Li J, Li W, Su J, Liu W, Altura BT, Altura BM. Peroxynitrite Induces Apoptosis in Rat Aortic Smooth Muscle Cells: Possible Relation to Vascular Diseases. Exp Biol Med (Maywood) 2016; 229:264-9. [PMID: 14988519 DOI: 10.1177/153537020422900307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
An emerging body of evidence is accumulating to suggest that in vivo formation of free radicals in the vasculature, such as peroxynitrite (ONOO–), and programmed cell death (i.e., apoptosis) play important roles in vascular diseases such as atherosclerosis, hypertension, and restenosis. The present study was designed to determine whether primary rat aortic smooth muscle cells (SMCs) undergo apoptosis following treatment with ONOO–. Direct exposure of primary rat aortic SMCs to ONOO– induced apoptosis in a concentration-dependent manner, as confirmed by means of quantitative fluorescence staining and TUNEL assays. ONOO–-induced apoptosis in rat aortic SMCs appears to involve activation of Ca2+-dependent endonucleases. Although the precise mechanisms by which peroxynitrite induces apoptosis in rat aortic SMCs need to be further investigated, the present, preliminary findings could be used to suggest that ONOO– formation in the vasculature may play roles in the processes of vascular diseases, such as atherosclerosis, hypertension, and restenosis, via adverse actions on blood vessels.
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MESH Headings
- Animals
- Aorta/drug effects
- Apoptosis/drug effects
- Calcium/metabolism
- Cell Survival/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Endonucleases/drug effects
- Endonucleases/metabolism
- In Situ Nick-End Labeling
- Male
- Microscopy, Fluorescence
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/pathology
- Peroxynitrous Acid/pharmacology
- Rats
- Rats, Wistar
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Affiliation(s)
- Jianfeng Li
- Department of Physiology, State University of New York, Downstate Medical Center, Brooklyn, New York 11203, USA
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7
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Effects of grain refinement on the biocorrosion and in vitro bioactivity of magnesium. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 57:294-303. [PMID: 26354267 DOI: 10.1016/j.msec.2015.07.033] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 07/13/2015] [Indexed: 12/16/2022]
Abstract
Magnesium is a new class of biodegradable metals potentially suitable for bone fracture fixation due to its suitable mechanical properties, high degradability and biocompatibility. However, rapid corrosion and loss in mechanical strength under physiological conditions render it unsuitable for load-bearing applications. In the present study, grain refinement was implemented to control bio-corrosion demonstrating improved in vitro bioactivity of magnesium. Pure commercial magnesium was grain refined using different amounts of zirconium (0.25 and 1.0 wt.%). Corrosion behavior was studied by potentiodynamic polarization (PDP) and mass loss immersion tests demonstrating corrosion rate decrease with grain size reduction. In vitro biocompatibility tests conducted by MC3T3-E1 pre-osteoblast cells and measured by DNA quantification demonstrate significant increase in cell proliferation for Mg-1 wt.% Zr at day 5. Similarly, alkaline phosphatase (ALP) activity was higher for grain refined Mg. Alloys were also tested for ability to support osteoclast differentiation using RAW264.7 monocytes with receptor activator of nuclear factor kappa-β ligand (RANKL) supplemented cell culture. Osteoclast differentiation process was observed to be severely restricted for smaller grained Mg. Overall, the results indicate grain refinement to be useful not only for improving corrosion resistance of Mg implants for bone fixation devices but also potentially modulate bone regeneration around the implant.
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Upadhyay Dhungel K, Kim TW, Sharma N, Bhattarai JP, Ah Park S, Han SK, Kim CJ. Magnesium increases iberiotoxin-sensitive large conductance calcium activated potassium currents on the basilar artery smooth muscle cells in rabbits. Neurol Res 2013; 34:11-6. [DOI: 10.1179/1743132811y.0000000049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kshitiz Upadhyay Dhungel
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Tae Woon Kim
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Naveen Sharma
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
| | - Janardhan Prasad Bhattarai
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Seon Ah Park
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Seong Kyu Han
- Department of Oral Physiology & Institute of Oral BioscienceSchool of Dentistry, Chonbuk National University, Jeonju, Korea
| | - Chul Jin Kim
- Cerebrovascular Laboratory-Department of NeurosurgeryResearch Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Jeonju, Korea
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Bobe K, Willbold E, Morgenthal I, Andersen O, Studnitzky T, Nellesen J, Tillmann W, Vogt C, Vano K, Witte F. In vitro and in vivo evaluation of biodegradable, open-porous scaffolds made of sintered magnesium W4 short fibres. Acta Biomater 2013; 9:8611-23. [PMID: 23542554 DOI: 10.1016/j.actbio.2013.03.035] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/23/2013] [Accepted: 03/22/2013] [Indexed: 11/27/2022]
Abstract
A cytocompatible and biocompatible, degradable, open-porous, mechanically adaptable metal scaffold made of magnesium alloy W4 melt-extracted short fibres was fabricated by liquid phase sintering. Cylindrical samples (3×5 mm) of sintered W4 short fibres were evaluated under in vitro (L929, HOB, eudiometer, weight loss) and in vivo conditions (rabbits: 6 and 12 weeks). The in vitro corrosion environment (e.g., temperature, flow, composition of corrosion solution, exposure time) significantly influenced the corrosion rates of W4 scaffolds compared with corrosion in vivo. Corrosion rates under cell culture conditions for 72 h varied from 1.05 to 3.43 mm y(-1) depending on the media composition. Corrosion rates measured in eudiometric systems for 24 h were ~24-27 times higher (3.88-4.43 mm y(-1)) than corrosion in vivo after 6 weeks (0.16 mm y(-1)). Moreover, it was found that the cell culture media composition significantly influences the ionic composition of the extract by selectively dissolving ions from W4 samples or their corrosion products. A pilot in vivo study for 6 and 12 weeks demonstrated active bone remodelling, no foreign body reaction and no clinical observation of gas formation during W4 scaffold implantation. Long-term in vivo studies need to be conducted to prove complete degradation of the W4 scaffold and total replacement by the host tissue.
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10
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Ortega O, Rodriguez I, Cobo G, Hinostroza J, Gallar P, Mon C, Ortiz M, Herrero JC, Di Gioia C, Oliet A, Vigil A. Lack of influence of serum magnesium levels on overall mortality and cardiovascular outcomes in patients with advanced chronic kidney disease. ISRN NEPHROLOGY 2013; 2013:191786. [PMID: 24959538 PMCID: PMC4045427 DOI: 10.5402/2013/191786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/06/2013] [Indexed: 11/23/2022]
Abstract
Background. Low serum magnesium has been associated with an increased cardiovascular risk in the general population and in dialysis patients. Our aim was to analyze the influence of serum magnesium on overall mortality and cardiovascular outcomes in patients with advanced CKD not yet on dialysis. Methods. Seventy patients with CKD stages 4 and 5 were included. After a single measurement of s-magnesium, patients were followed a mean of 11 months. Primary end-point was death of any cause, and secondary end-point was the occurrence of fatal or nonfatal CV events. Results. Basal s-magnesium was within normal range (2.1 ± 0.3 mg/dL), was lower in men (P = 0.008) and in diabetic patients (P = 0.02), and was not different (P = 0.2) between patients with and without cardiopathy. Magnesium did not correlate with PTH, calcium, phosphate, albumin, inflammatory parameters (CRP), and cardiac (NT-proBNP) biomarkers but correlated inversely (r = −0.23; P = 0.052) with the daily dose of loop diuretics. In univariate and multivariate Cox proportional hazard models, magnesium was not an independent predictor for overall mortality or CV events. Conclusions. Our results do not support that serum magnesium can be an independent predictor for overall mortality or future cardiovascular events among patients with advanced CKD not yet on dialysis.
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Affiliation(s)
- Olimpia Ortega
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Isabel Rodriguez
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Gabriela Cobo
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Julie Hinostroza
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Paloma Gallar
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Carmen Mon
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Milagros Ortiz
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Juan Carlos Herrero
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Cristina Di Gioia
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Aniana Oliet
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
| | - Ana Vigil
- Nephrology Service, Hospital Severo Ochoa, Avenida Orellana s/n, Leganés 28911, Madrid, Spain
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11
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Chakraborty P, Ghosh S, Goswami SK, Kabir SN, Chakravarty B, Jana K. Altered trace mineral milieu might play an aetiological role in the pathogenesis of polycystic ovary syndrome. Biol Trace Elem Res 2013; 152:9-15. [PMID: 23322284 DOI: 10.1007/s12011-012-9592-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 12/21/2012] [Indexed: 10/27/2022]
Abstract
Insulin resistance is a very common associate of polycystic ovary syndrome (PCOS). Pathophysiology in relation with the essential elements including copper, magnesium, zinc, manganese, chromium, and calcium has been reported in women with insulin resistance. This prospective study was designed to explore whether the women with PCOS do exhibit altered serum element levels in association with/without insulin resistance. One hundred and thirty-two women with PCOS and forty-six control women were studied. Women with PCOS were further divided based on the presence of insulin resistance (insulin resistant: n = 50; non-insulin resistant: n = 82). In all women, basal levels of gonadotropins, prolactin, testosterone, insulin, glucose, and the six different elements were measured. Serum levels of testosterone (p < 0.001), luteinizing hormone (p < 0.05), and fasting insulin (p < 0.004) were significantly higher in the PCOS population compared to controls as well as PCOS women without insulin resistance. Women with PCOS exhibited a significantly high calcium (p < 0.04) and lower manganese levels (p < 0.002) when compared to controls. However, the PCOS women with insulin resistance exhibited significantly lower serum levels of magnesium and chromium (p < 0.04), in addition to higher levels of zinc and copper (p < 0.04). The differences in calcium (p < 0.03) and manganese levels (p < 0.0001) became aggravated with the presence of insulin resistance when compared to control as well as PCOS women without insulin resistance. In PCOS-associated insulin resistance, circulating serum magnesium (r = -0.31; p < 0.03) and chromium (r = -0.38; p < 0.006) status significantly correlated with fasting insulin levels. We conclude that imbalanced element status may be a key foundation for insulin resistance in PCOS. The findings in this study should be investigated with further trials in order to obtain new insights into PCOS.
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Affiliation(s)
- Pratip Chakraborty
- Department of Infertility, Institute of Reproductive Medicine, Salt Lake City, Kolkata 700106, India
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12
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Roy M, Balla VK, Bandyopadhyay A, Bose S. MgO-doped tantalum coating on Ti: microstructural study and biocompatibility evaluation. ACS APPLIED MATERIALS & INTERFACES 2012; 4:577-80. [PMID: 22248182 PMCID: PMC3288316 DOI: 10.1021/am201365e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pure and MgO incorporated Ta coatings were prepared on Cp-Ti substrate using laser engineered net shaping (LENS), which resulted in diffuse coating-substrate interface. MgO was found along the Ta grain boundaries in the Ta matrix that increased the coating hardness from 185 ± 2.7 HV to 794 ± 93 HV. In vitro biocompatibility study showed excellent early cellular attachment and later stage proliferation in MgO incorporated coatings. The results indicated that although Ta coatings had higher biocompatibility than Ti, it could further be improved by incorporating MgO in the coating, while simultaneously improving the mechanical properties.
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Affiliation(s)
- Mangal Roy
- W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
| | | | - Amit Bandyopadhyay
- W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
| | - Susmita Bose
- W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USA
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13
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Altura BM, Shah NC, Shah G, Zhang A, Li W, Zheng T, Perez-Albela JL, Altura BT. Short-term magnesium deficiency upregulates ceramide synthase in cardiovascular tissues and cells: cross-talk among cytokines, Mg2+, NF-κB, and de novo ceramide. Am J Physiol Heart Circ Physiol 2012; 302:H319-32. [DOI: 10.1152/ajpheart.00453.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The present study tested the hypotheses that 1) short-term dietary deficiency (MgD) of magnesium (21 days) would result in the upregulation of ceramide synthase (CS) in left ventricular (LV), right ventricular, atrial, and aortic smooth muscle, as well as induce a synthesis/release of select cytokines and chemokines into the LV and aortic smooth muscle and serum; 2) exposure of primary cultured vascular smooth muscle cells (VSMCs) to low extracellular Mg concentration would lead to the synthesis/release of select cytokines/chemokines, activation of N-SMase, and the de novo synthesis of ceramide; and 3) inhibition of CS by fumonisin B1 (FB1) or inhibition of neutral sphingomyelinase (N-SMase) by scyphostatin (SCY) in VSMCs exposed to low Mg would result in reductions in the levels of the cytokines/chemokines and lowered levels of ceramide concomitant with inhibition of NF-κB activation. The data indicated that short-term MgD (10% normal dietary intake) resulted in the upregulation of CS in ventricular, atrial, and aortic smooth muscles coupled to the synthesis/release of 12 different cytokines/chemokines, as well as activation of NF-κB in the LV and aortic smooth muscle and sera; even very low levels of water-borne Mg (e.g., 15 mg·l−1·day−1) either prevented or ameliorated the upregulation and synthesis of the cytokines/chemokines. Our experiments also showed that VSMCs exposed to low extracellular Mg resulted in the synthesis of 5 different cytokines and chemokines concomitant with synthesis/release of ceramide. However, inhibition of the synthesis and release of ceramide by either FB1 or SCY attenuated, markedly , the generation of ceramide, release of the cytokines/chemokines, and activation of NF-κB (as measured by activated p65 and cRel).
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Affiliation(s)
- Burton M. Altura
- Departments of 1Physiology and Pharmacology and
- Medicine,
- Center for Cardiovascular and Muscle Research, and
- School of Graduate Studies Program in Molecular and Cellular Science, State University of New York Downstate Medical Center, Brooklyn
- Bio-Defense Systems, Incorporated, Rockville Centre, New York, and
| | | | - Gatha Shah
- Departments of 1Physiology and Pharmacology and
| | - Aimin Zhang
- Departments of 1Physiology and Pharmacology and
| | - Wenyan Li
- Departments of 1Physiology and Pharmacology and
| | - Tao Zheng
- Departments of 1Physiology and Pharmacology and
| | | | - Bella T. Altura
- Departments of 1Physiology and Pharmacology and
- Center for Cardiovascular and Muscle Research, and
- School of Graduate Studies Program in Molecular and Cellular Science, State University of New York Downstate Medical Center, Brooklyn
- Bio-Defense Systems, Incorporated, Rockville Centre, New York, and
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Kircelli F, Peter ME, Sevinc Ok E, Celenk FG, Yilmaz M, Steppan S, Asci G, Ok E, Passlick-Deetjen J. Magnesium reduces calcification in bovine vascular smooth muscle cells in a dose-dependent manner. Nephrol Dial Transplant 2011; 27:514-21. [PMID: 21750166 PMCID: PMC3275783 DOI: 10.1093/ndt/gfr321] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Background. Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs). Methods. BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription–polymerase chain reaction and annexin V staining, respectively. Results. Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification. Conclusions. Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations.
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Affiliation(s)
- Fatih Kircelli
- Division of Nephrology, Ege University School of Medicine, Izmir, Turkey.
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15
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Katayama Y, Minami H, Enomoto M, Takano T, Hayashi S, Lee YK. Antenatal magnesium sulfate and the postnatal response of the ductus arteriosus to indomethacin in extremely preterm neonates. J Perinatol 2011; 31:21-4. [PMID: 20505743 DOI: 10.1038/jp.2010.62] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The aim of this study is to evaluate the influence of antenatal magnesium sulfate (MgSO(4)) treatment on the clinical responsiveness of the ductus arteriosus to indomethacin prophylaxis and on that of symptomatic patent ductus arteriosus (sPDA) to indomethacin treatment in premature neonates. STUDY DESIGN This is a retrospective study of 160 consecutively admitted neonates with a gestational age of <28 weeks (41 MgSO(4) exposed and 119 controls) who received indomethacin prophylaxis. RESULT Incidence of early closure of the ductus arteriosus was lower in the MgSO(4)-exposed neonates than in the control group (59 vs 84%, respectively; P=0.002), whereas incidence of an sPDA was higher (46 vs 24%, respectively; P=0.006). Response to indomethacin treatment was similar between the two groups. Logistic regression analysis indicated increased risk of failure of early ductus arteriosus closure following antenatal MgSO(4) treatment (odds ratio, 4.03; P=0.002). CONCLUSION In extremely preterm neonates, antenatal MgSO(4) treatment reduces clinical responsiveness of the ductus arteriosus to indomethacin prophylaxis but not that of sPDA to indomethacin treatment.
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Affiliation(s)
- Y Katayama
- Division of Neonatology, Department of Pediatrics, Takatsuki General Hospital, Takatsuki City, Osaka, Japan.
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16
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Altura BM, Shah NC, Li Z, Jiang XC, Zhang A, Li W, Zheng T, Perez-Albela JL, Altura BT. Short-term magnesium deficiency upregulates sphingomyelin synthase and p53 in cardiovascular tissues and cells: relevance to the de novo synthesis of ceramide. Am J Physiol Heart Circ Physiol 2010; 299:H2046-55. [PMID: 20935146 PMCID: PMC3774185 DOI: 10.1152/ajpheart.00671.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/29/2010] [Indexed: 02/03/2023]
Abstract
The present study tested the hypotheses that 1) short-term dietary deficiency of magnesium (21 days) in rats would result in the upregulation of sphingomyelin synthase (SMS) and p53 in cardiac and vascular (aortic) smooth muscles, 2) low levels of Mg(2+) added to drinking water would either prevent or greatly reduce the upregulation of both SMS and p53, 3) exposure of primary cultured vascular smooth muscle cells (VSMCs) to low extracellular Mg(2+) concentration ([Mg(2)](o)) would lead to the de novo synthesis of ceramide, 4) inhibition of either SMS or p53 in primary culture VSMCs exposed to low [Mg(2+)](o) would lead to reductions in the levels of de novo ceramide synthesis, and 5) inhibition of sphingomyelin palmitoyl-CoA transferase (SPT) or ceramide synthase (CS) in primary cultured VSMCs exposed to low [Mg(2+)](o) would lead to a reduction in the levels of de novo ceramide synthesis. The data indicated that short-term magnesium deficiency (10% normal dietary intake) resulted in the upregulation of SMS and p53 in both ventricular and aortic smooth muscles; even very low levels of water-borne Mg(2+) (e.g., 15 mg·l(-1)·day(-1)) either prevented or ameliorated the upregulation in SMS and p53. Our experiments also showed that VSMCs exposed to low [Mg(2+)](o) resulted in the de novo synthesis of ceramide; the lower the [Mg(2+)](o), the greater the synthesis of ceramide. In addition, the data indicated that inhibition of either SMS, p53, SPT, or CS in VSMCs exposed to low [Mg(2+)](o) resulted in marked reductions in the de novo synthesis of ceramide.
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Affiliation(s)
- Burton M Altura
- Department of Physiology and Pharmacology, State University of New York, Brooklyn, New York, USA.
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17
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Zheng T, Li W, Altura BT, Shah NC, Altura BM. Sphingolipids regulate [Mg2+]o uptake and [Mg2+]i content in vascular smooth muscle cells: potential mechanisms and importance to membrane transport of Mg2+. Am J Physiol Heart Circ Physiol 2010; 300:H486-92. [PMID: 21112948 DOI: 10.1152/ajpheart.00976.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sphingolipids have a variety of important signaling roles in mammalian cells. We tested the hypothesis that certain sphingolipids and neutral sphingomyelinase (N-SMase) can regulate intracellular free magnesium ions ([Mg2+]i) in vascular smooth muscle (VSM) cells. Herein, we show that several sphingolipids, including C2-ceramide, C8-ceramide, C16-ceramide, and sphingosine, as well as N-SMase, have potent and direct effects on content and mobilization of [Mg2+]i in primary cultured rat aortic smooth muscle cells. All of these sphingolipid molecules increase, rapidly, [Mg2+]i in these vascular cells in a concentration-dependent manner. The increments of [Mg2+]i, induced by these agents, are derived from influx of extracellular Mg2+ and are extracellular Ca2+ concentration-dependent. Phospholipase C and Ca2+/calmodulin/Ca2+-ATPase activity appear to be important in the sphingolipid-induced rises of [Mg2+]i. Activation of certain PKC isozymes may also be required for sphingolipid-induced rises in [Mg2+]i. These novel results suggest that sphingolipids may be homeostatic regulators of extracellular Mg2+ concentration influx (and transport) and [Mg2+]i content in vascular muscle cells.
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Affiliation(s)
- Tao Zheng
- Department of Physiology and Pharmacology, Center For Cardiovascular and Muscle Research, The School of Graduate Studies Program in Molecular and Cellular Science, State University of New York, Box 31, SUNY Health Science Center at Brooklyn, 450 Clarkson Ave., Brooklyn, NY 11203, USA
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18
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Abed E, Moreau R. Importance of melastatin-like transient receptor potential 7 and magnesium in the stimulation of osteoblast proliferation and migration by platelet-derived growth factor. Am J Physiol Cell Physiol 2009; 297:C360-8. [DOI: 10.1152/ajpcell.00614.2008] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bone is a dynamic tissue that is continuously being remodeled throughout life. Specialized cells called osteoclasts transiently break down old bone (resorption process) at multiple sites as other cells known as osteoblasts are replacing it with new tissue (bone formation). Usually, both resorption and formation processes are in balance and thereby maintain skeletal strength and integrity. This equilibrium is assured by the coordination of proliferation, migration, differentiation, and secretory functions of the osteoblasts, which are essential for adequate formation and resorption processes. Disturbances of this equilibrium may lead to decreased bone mass (osteoporosis), increased bone fragility, and susceptibility to fractures. Epidemiological studies have linked insufficient dietary magnesium (Mg2+) intake in humans with low bone mass and osteoporosis. Here, we investigated the roles of Mg2+ and melastatin-like transient receptor potential 7 (TRPM7), known as Mg2+ channels, in human osteoblast cell proliferation and migration induced by platelet-derived growth factor (PDGF), which has been involved in the bone remodeling process. PDGF promoted an influx of Mg2+, enhanced cell migration, and stimulated the gene expression of TRPM7 channels in human osteoblast MG-63 cells. The stimulation of osteoblast proliferation and migration by PDGF was significantly reduced under culture conditions of low extracellular Mg2+ concentrations. Silencing TRPM7 expression in osteoblasts by specific small interfering RNA prevented the induction by PDGF of Mg2+ influx, proliferation, and migration. Our results indicate that extracellular Mg2+ and TRPM7 are important for PDGF-induced proliferation and migration of human osteoblasts. Thus Mg2+ deficiency, a common condition among the general population, may be associated with altered osteoblast functions leading to inadequate bone formation and the development of osteoporosis.
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19
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Houston MC, Harper KJ. Potassium, magnesium, and calcium: their role in both the cause and treatment of hypertension. J Clin Hypertens (Greenwich) 2008; 10:3-11. [PMID: 18607145 PMCID: PMC8109864 DOI: 10.1111/j.1751-7176.2008.08575.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Despite advances in the prevention and treatment of hypertension over the past decade, hypertension remains an important public health challenge. Recent efforts to reduce the prevalence of hypertension have focused on nonpharmacologic means, specifically diet. An increased intake of minerals such as potassium, magnesium, and calcium by dietary means has been shown in some but not all studies to reduce blood pressure in patients with hypertension. This review will discuss the roles of potassium, magnesium, and calcium in the prevention and treatment of essential hypertension with specific emphasis on clinical trial evidence, mechanism of action, and recommendations for dietary intake of these minerals. A high intake of these minerals through increased consumption of fruits and vegetables may improve blood pressure levels and reduce coronary heart disease and stroke.
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Affiliation(s)
- Mark C Houston
- Vanderbilt University School of Medicine, Nashville, TN 37205, USA.
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20
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Touyz RM. Transient receptor potential melastatin 6 and 7 channels, magnesium transport, and vascular biology: implications in hypertension. Am J Physiol Heart Circ Physiol 2008; 294:H1103-18. [PMID: 18192217 DOI: 10.1152/ajpheart.00903.2007] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnesium, an essential intracellular cation, is critically involved in many biochemical reactions involved in the regulation of vascular tone and integrity. Decreased magnesium concentration has been implicated in altered vascular reactivity, endothelial dysfunction, vascular inflammation, and structural remodeling, processes important in vascular changes and target organ damage associated with hypertension. Until recently, very little was known about mechanisms regulating cellular magnesium homeostasis, and processes controlling transmembrane magnesium transport had been demonstrated only at the functional level. Two cation channels of the transient receptor potential melastatin (TRPM) cation channel family have now been identified as magnesium transporters, TRPM6 and TRPM7. These unique proteins, termed chanzymes because they possess a channel and a kinase domain, are differentially expressed, with TRPM6 being found primarily in epithelial cells and TRPM7 occurring ubiquitously. Vascular TRPM7 is modulated by vasoactive agents, pressure, stretch, and osmotic changes and may be a novel mechanotransducer. In addition to its magnesium transporter function, TRPM7 has been implicated as a signaling kinase involved in vascular smooth muscle cell growth, apoptosis, adhesion, contraction, cytoskeletal organization, and migration, important processes involved in vascular remodeling associated with hypertension and other vascular diseases. Emerging evidence suggests that vascular TRPM7 function may be altered in hypertension. This review discusses the importance of magnesium in vascular biology and implications in hypertension and highlights the transport systems, particularly TRPM6 and TRPM7, which may play a role in the control of vascular magnesium homeostasis. Since the recent identification and characterization of Mg2+-selective transporters, there has been enormous interest in the field. However, there is still a paucity of information, and much research is needed to clarify the exact mechanisms of magnesium regulation in the cardiovascular system and the implications of aberrant transmembrane magnesium transport in the pathogenesis of hypertension and other vascular diseases.
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Affiliation(s)
- Rhian M Touyz
- Kidney Research Center, Ottawa Heallth Research Institute, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5.
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21
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Mustafa S, Thulesius O, Elgazzar AH, Ismael HN. Synergistic effects of ethanol and hyperthermia on carotid artery vasoconstriction. Clin Physiol Funct Imaging 2007; 27:185-90. [PMID: 17445070 DOI: 10.1111/j.1475-097x.2007.00733.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Heatstroke is a serious condition and clinical studies indicate that vascular stroke increases with excessive consumption of alcohol (ethanol). It was our objective to test the influence of ethanol on cerebral perfusion at normal and higher temperatures. METHODS Recording of isometric tension in rabbit carotid artery strips in organ baths with different concentrations of ethanol at 37 degrees C and during hyperthermia (39-43 degrees C) and scintigraphic cerebral imaging of a radioactive isotope in the control situation and during hyperthermia. RESULTS Stepwise heating induced reproducible reversible graded contraction, proportional to temperature. At high concentrations (toxic levels), ethanol induced an increase in tension and heating potentiated these responses. Extracellular Mg(2+) potentiated both heat-induced contraction and ethanol-induced contraction while extracellular Ca(2+) had no effect on these responses. During hyperthermia and ethanol scintigraphic isotope uptake was reduced in cortical and cerebellar regions. CONCLUSIONS Carotid artery vasomotor tone is temperature dependent and heating induces vasoconstriction. Alcohol (ethanol) at 37 degrees C elicited carotid artery contraction at high concentrations (toxic levels) but at any concentration during elevated temperature (39-43 degrees C). Ethanol potentiated the effect of hyperthermia-induced vasoconstriction and reduced cerebral perfusion as shown by radionuclide imaging. The synergistic effect of ethanol and hyperthermia may induce heat stroke and brain damage.
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Affiliation(s)
- S Mustafa
- College of Health Sciences, The Public Authority for Applied Education and Training, Safat, Kuwait.
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22
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Accelerated thymus involution in magnesium-deficient rats is related to enhanced apoptosis and sensitivity to oxidative stress. Br J Nutr 2007. [DOI: 10.1017/s0007114599000690] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Experimental Mg deficiency leads to alterations in the immune response. Reduction of thymus weight and histological changes were previously observed in Mg-deficient rats after several weeks on a deficient diet, suggesting that functions of this immune organ may be affected by Mg deficiency. More recently, changes in the immune system during early Mg deficiency were shown. Thus, in the present study we examined modifications in the thymus during the early stages of Mg deficiency in weanling rats. From our results, it appears that Mg deficiency accelerates thymus involution. The assessment of apoptosis (enumeration of apoptotic cells on the basis of morphological criteria and intranucleosomal degradation of genomic DNA) showed greater values in thymuses from Mg-deficient rats as compared with controls. This was observed very early, since a significant difference was shown on the second day of deficiency, before reduced weight of thymus, which was recorded in the later period. These results indicate the relationship of accelerated thymus involution with an active process of cell death. Mg deficiency led to histological changes in the thymus. In the early stage of deficiency (second day) the presence of inflammatory cells was shown, suggesting that the inflammatory process was already occurring in the tissue studied. Later (eighth day) an increased proportion of epithelial reticular cells in the cortex was shown, indicating a remodelling process occurring in this period. Enhanced susceptibility to peroxidation also occurred very early during Mg deficiency. It may be hypothesized that disturbances in Mg status of short duration could have cellular effects with various deleterious consequences.
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Abstract
The purpose of the present study was to determine the effects of Mg deficiency and supplementation on the mechanical properties of the rat common carotid artery. The internal diameter and intra-arterial pressure of carotid artery were measured continuously using an echo-tracking device. Systolic, diastolic and mean intra-arterial pressures were not significantly different in Mg-deficient, -supplemented or control rats. Histological examination showed a larger cross-sectional area, increased intima-media thickness and a greater media:lumen value in carotid artery of Mg-deficient rats, indicating that Mg deficiency may directly stimulate growth and/or proliferation of arterial wall components. In addition, we observed a negative linear relationship between intima-media thickness and plasma Mg concentration, suggesting that increased Mg intake may counteract arterial wall hypertrophy. Neither Mg deficiency nor supplementation modified the arterial distensibilityv.intra-arterial pressure curve or the Eincv.wall stress curve, indicating that dietary Mg intake did not modify wall stiffness in young rats. At mean intra-arterial pressure, the stress and Eincvalues were, however, significantly lower in Mg-deficient rats (P<0·05 in both cases); this finding could be related to the alteration in the geometry of the carotid artery. In conclusion, these findings suggest that Mg deficiency modifies the mechanical properties of the common carotid artery in young rats. Since Mg deficiency is considered a risk factor, these mechanical alterations could contribute to the development of atherosclerosis, hypertension and cardiovascular diseases.
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Sontia B, Touyz RM. Role of magnesium in hypertension. Arch Biochem Biophys 2006; 458:33-9. [PMID: 16762312 DOI: 10.1016/j.abb.2006.05.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Accepted: 05/03/2006] [Indexed: 12/15/2022]
Abstract
Magnesium affects blood pressure by modulating vascular tone and reactivity. It acts as a calcium channel antagonist, it stimulates production of vasodilator prostacyclins and nitric oxide and it alters vascular responses to vasoactive agonists. Magnesium deficiency has been implicated in the pathogenesis of hypertension with epidemiological and experimental studies demonstrating an inverse correlation between blood pressure and serum magnesium levels. Magnesium also influences glucose and insulin homeostasis, and hypomagnesemia is associated with metabolic syndrome. Although most epidemiological and experimental studies support a role for low magnesium in the pathophysiology of hypertension, data from clinical studies have been less convincing. Furthermore, the therapeutic value of magnesium in the management of hypertension is unclear. The present review addresses the role of magnesium in the regulation of vascular function and blood pressure and discusses the implications of magnesium deficiency in experimental and clinical hypertension, in metabolic syndrome and in pre-eclampsia.
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Affiliation(s)
- Bruno Sontia
- Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ontario, Canada K1H 8M5
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25
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Sakamoto T, Takasu A, Saitoh D, Kaneko N, Yanagawa Y, Okada Y. Ionized magnesium in the cerebrospinal fluid of patients with head injuries. ACTA ACUST UNITED AC 2005; 58:1103-9. [PMID: 15995455 DOI: 10.1097/01.ta.0000169950.51735.c4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND In head injury patients, a decrease in the serum ionized magnesium (iMg) concentration is considered to be related to the severity of the injury, however, this phenomenon is still not completely understood. The cerebrospinal fluid (CSF) iMg concentration has not been well documented under such conditions and, moreover, its normal value has not yet been established. We hereby intended to investigate the role of the iMg concentration and other parameters in both the serum and CSF of head injury patients and identify any relationship with other parameters. MATERIALS AND METHODS The subjects consisted of head injury patients without any other serious injuries. Ten healthy volunteers were selected as control subjects. Arterial blood and CSF specimens were simultaneously obtained and measured. We measured the Glasgow Coma Scale scores (GCS), the intracranial pressure (ICP), pH, po2, pco2, sodium, potassium, iCa, iMg, glucose, lactate, urea nitrogen. All data are expressed as the mean+/-SD and the units of iMg and iCa (corrected under pH 7.40) are given in mmol/L. RESULTS In the healthy subjects, the iMg concentration in the serum/CSF was 0.48 +/- 0.02 / 0.66 +/- 0.14, and iCa was 1.14 +/- 0.05 / 0.94 +/- 0.07. The GCS of the 15 head injury subjects at examination was 8.7 +/- 4.5. When the subjects were divided into 3 groups according to the GCS level (3 and 4, 5-8, and > or =9) at the time of examination, the serum iMg concentration was thus found to be related to the severity of injury based on the GCS level (p = 0.028), but not the CSF iMg concentration (p = 0.89). No relationship was observed between the iMg concentration in the serum and CSF when all specimens were compared, but an extremely close correlation was seen in the group with GCS 3 and 4 (p < 0.0001, r = 0.995), although no such correlation was seen in the other 2 groups (p = 0.12, r = -0.56 in the group with GCS 5-8, and p = 0.26, r = -0.35 in the group with GCS > or = 9). There was a significant correlation between the serum iMg and iCa (p = 0.0093, r = 0.47), and also between the CSF iMg and iCa concentrations (p < 0.0001, r = 0.67). CONCLUSION The serum iMg concentration has been suggested to possibly affect the neurologic state through CSF iMg in patients with the most severe head injury. In patients with moderate or mild head injuries, however, the ionized magnesium concentration is also probably associated with the degree of neurologic deficit based on the ionized calcium level. The CSF and serum ionized magnesium dissociation may thus result from the slow movement of ionized magnesium through the blood brain barrier.
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26
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McCarty MF. Magnesium may mediate the favorable impact of whole grains on insulin sensitivity by acting as a mild calcium antagonist. Med Hypotheses 2005; 64:619-27. [PMID: 15617878 DOI: 10.1016/j.mehy.2003.10.034] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2003] [Accepted: 10/17/2003] [Indexed: 12/15/2022]
Abstract
Recent epidemiology has linked high consumption of whole grains with reduced risk for diabetes, coronary disease, stroke, and various types of cancer; there is reason to suspect that improved insulin sensitivity is largely responsible for this protection. This phenomenon may be partially explained by the lower glycemic indices of some whole grain food products in comparison to their fiber-depleted analogs. Nonetheless, the fact that whole wheat flour promotes insulin sensitivity relative to white flour--and yet has a near-identical glycemic index--suggests that certain nutrients or phytochemicals in whole wheat, depleted by the refining process, promote preservation of insulin sensitivity. Magnesium is a likely candidate in this regard; magnesium deficiency promotes insulin resistance in rodents and in humans, whereas supplemental magnesium has been found to prevent type 2 diabetes in rodent models of this syndrome, and to improve the insulin sensitivity of elderly or diabetic humans. Magnesium-rich diets as well as above-average serum magnesium are associated with reduced diabetes risk in prospective epidemiology, and with greater insulin sensitivity in cross-sectional studies; moreover, other types of magnesium-rich foods--dairy products, legumes, and nuts--have been linked to decreased diabetes risk in prospective studies. The biochemical role of magnesium in support of insulin function is still poorly understood. In light of evidence that magnesium can function as a mild natural calcium antagonist, it is interesting to note suggestive evidence that increases in intracellular free calcium may compromise the insulin responsiveness of adipocytes and skeletal muscle, and may indeed play a pathogenic role in the insulin resistance syndrome. Thus, it is proposed that some or all of the favorable impact of good magnesium status on insulin function may reflect antagonism of the induction or effects of increased intracellular free calcium. Further research concerning the potential health benefits of long-term magnesium supplementation is clearly warranted. These considerations, however, should not detract from efforts to better inform the public regarding the strong desirability of choosing whole grain products in preference to refined grains.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe Street, San Diego, CA 92109, USA.
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27
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Li J, Li W, Liu W, Altura BT, Altura BM. Mechanisms of hydroxyl radical-induced contraction of rat aorta. Eur J Pharmacol 2004; 499:171-8. [PMID: 15363964 DOI: 10.1016/j.ejphar.2004.07.094] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Revised: 07/16/2004] [Accepted: 07/20/2004] [Indexed: 11/19/2022]
Abstract
The present study was designed to investigate the effects of hydroxyl radicals (*OH), generated via the Fe2+-mediated Fenton reaction, on isolated rat aortic rings with and without endothelium. In the absence of any vasoactive agent, generation of *OH alone elicited an endothelium-independent contraction in rat aortic rings in a concentration-dependent manner. Hydroxyl radical-induced contractions of denuded rat aortic rings appeared, however, to be slightly stronger than those on intact rat aortic rings. The contractile responses to *OH were neither reversible nor reproducible in the same ring; even small concentrations of *OH radicals resulted in tachyphylaxis. Removal of extracellular calcium ions (Ca2+) or buffering intracellular Ca2+ with 10 microM acetyl methyl ester of bis(o-aminophenoxy) ethane-N,N,N',N',-tetraacetic acid (BAPTA-AM) significantly attenuated the contractile actions of *OH radicals. The presence of 1 microM staurosporine, 1 microM bisindolylmaleimide I, 1 microM Gö6976 [inhibitor of protein kinase C (PKC)], 2 microM PD-980592 (inhibitor of ERK), 10 microM genistein, and 1 microM wortmannin significantly inhibited the contractions induced by *OH. Proadifen (10 microM), on the other hand, significantly potentiated the hydroxyl radical-induced contractions. Exposure of primary cultured aortic smooth muscle cells to *OH produced significant, rapid rises of intracellular free Ca2+ ([Ca2+]i). Several, specific antagonists of possible endogenously formed vasoconstrictors did not inhibit or attenuate either hydroxyl radical-induced contractions or the elevation of [Ca2+]i. Our new results suggest that hydroxyl radical-triggered contractions on rat aortic rings are Ca2+-dependent. Several intracellular signal transduction systems seem to play some role in hydroxyl radical-induced vasoconstriction of rat aortic rings.
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MESH Headings
- Androstadienes/pharmacology
- Animals
- Aorta/drug effects
- Aorta/physiology
- Calcium/metabolism
- Calcium/pharmacology
- Carbazoles/pharmacology
- Cells, Cultured
- Cytochrome P-450 Enzyme Inhibitors
- Dose-Response Relationship, Drug
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- Ferrous Compounds/pharmacology
- Genistein/pharmacology
- Hydrogen Peroxide/pharmacology
- Hydroxyl Radical/pharmacology
- In Vitro Techniques
- Indoles/pharmacology
- Male
- Maleimides/pharmacology
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Phosphoinositide-3 Kinase Inhibitors
- Proadifen/pharmacology
- Protein Kinase C/antagonists & inhibitors
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Rats
- Rats, Wistar
- Staurosporine/pharmacology
- Vasoconstriction/drug effects
- Wortmannin
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Affiliation(s)
- Jianfeng Li
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, NY 11203-2056, USA
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28
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Su J, Li J, Li W, Altura BT, Altura BM. Cocaine induces apoptosis in cerebral vascular muscle cells: potential roles in strokes and brain damage. Eur J Pharmacol 2004; 482:61-6. [PMID: 14660005 DOI: 10.1016/j.ejphar.2003.09.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cocaine abuse is known to induce different types of brain-microvascular damage and many adverse cerebrovascular effects, including cerebral vasculitis, intracranial hemorrhage, cerebral infarction and stroke. A major physiological event leading to these pathophysiological actions of cocaine could be apoptosis. Whether cocaine can cause brain-microvascular pathology and vascular toxicity by inducing apoptosis of cerebral vascular smooth muscle cells is not known. This study, using several different methods to discern apoptosis, was designed to investigate if primary cultured canine cerebral vascular smooth muscle cells can undergo apoptosis when treated with cocaine. After treatment with cocaine (10(-6)-10(-3) M) for 12-24 h, the death rates of cerebral vascular smooth muscle cells increased in a concentration-dependent manner compared with controls. Morphological analysis of cerebral vascular smooth muscle cells using confocal fluoresence microscopy showed that the percentage of apoptotic cerebral vascular smooth muscle cells increased after cocaine (10(-6)-10(-3) M) treatment in a concentration-dependent manner. TUNEL assays also showed positive results for cerebral vascular smooth muscle cells treated with cocaine. These results clearly demonstrate that cerebral vascular smooth muscle cells can undergo rapid apoptosis in response to cocaine in a concentration-dependent manner. Cocaine-induced apoptosis may thus play a major role in brain-microvascular damage, cerebral vascular toxicity and strokes.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Apoptosis/physiology
- Basilar Artery/drug effects
- Basilar Artery/pathology
- Basilar Artery/physiology
- Cells, Cultured
- Cocaine/pharmacology
- Cocaine/toxicity
- Dogs
- Dose-Response Relationship, Drug
- Hypoxia, Brain/chemically induced
- Hypoxia, Brain/pathology
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiology
- Stroke/chemically induced
- Stroke/pathology
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Affiliation(s)
- Jialin Su
- Department of Physiology and Pharmacology, Downstate Medical Center, State University of New York, 450 Clarkson Avenue, Box 31, Brooklyn, NY 11203-2056, USA
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29
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Li W, Su J, Sehgal S, Altura BT, Altura BM. Cocaine-induced relaxation of isolated rat aortic rings and mechanisms of action: possible relation to cocaine-induced aortic dissection and hypotension. Eur J Pharmacol 2004; 496:151-8. [PMID: 15288586 DOI: 10.1016/j.ejphar.2004.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 05/27/2004] [Accepted: 06/08/2004] [Indexed: 10/26/2022]
Abstract
Cocaine HCl is well known for its toxic effects on the cardiovascular system, but little is known about its effects on different regional blood vessels. We designed experiments to determine if cocaine HCl could influence the tension of isolated aortic rings, i.e., induce contraction or relaxation. Surprisingly, cocaine HCl (1 x 10(-5) to 6 x 10(-3) M) relaxed isolated aortic rings precontracted by phenylephrine in a concentration-dependent manner. No significant differences were found between intact or denuded isolated aortic rings (P>0.05). The maximal % relaxations of intact vs. denuded isolated aortic rings were 108.9+/-24.3% vs. 99.5+/-8.3% (P>0.05). Cocaine HCl, 2 x 10(-3) M, was found to inhibit contractions by phenylephrine; EC50s were increased (P<0.01) and Emax's were decreased (51.3+/-16.4% vs. 89.8+/-10.6%, P<0.01). A variety of amine antagonists could not inhibit the relaxant effects of cocaine HCl (P>0.05). The cyclooxygenase-1 inhibitor, indomethacin, also failed to inhibit relaxations induced by cocaine HCl (P>0.05). Neither L-arginine, NG-monomethyl-L-arginine (L-NMMA), nor methylene blue could inhibit the relaxations induced by cocaine HCl (P>0.05), suggesting cocaine HCl does not relax isolated aortic rings by inducing the synthesis or release of nitric oxide (NO) or prostanoids from either endothelial or vascular muscle cells. Inhibitors of cAMP, cGMP and protein kinase G (PKG) also failed to inhibit cocaine-induced relaxations. Cocaine HCl (1 x 10(-5) to 6 x 10(-3) M) could also relax isolated aortic rings precontracted by phenylephrine in high K+ depolarizing buffer. Surprisingly, calyculin A, an inhibitor of myosin light chain (MLC) phosphatase, inhibited cocaine-induced relaxations in a concentration-dependent manner, suggesting the probable importance of cocaine-induced MLC phosphatase activation in rat aortic smooth muscle cells. It was also found that cocaine HCl could dose-dependently inhibit Ca2+-induced contractions of isolated aortic rings in high K+-Ca2+-free buffer, suggesting that cocaine HCl may inhibit Ca2+ influx and/or intracellular release.
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Affiliation(s)
- Wenyan Li
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Box 31, 450 Clarkson Avenue, Brooklyn, NY 11203-2056, USA
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30
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Adrian M, Laurant P, Berthelot A. EFFECT OF MAGNESIUM ON MECHANICAL PROPERTIES OF PRESSURIZED MESENTERIC SMALL ARTERIES FROM OLD AND ADULT RATS. Clin Exp Pharmacol Physiol 2004; 31:306-13. [PMID: 15191403 DOI: 10.1111/j.1440-1681.2004.03992.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of the present study was to determine the effects of magnesium (Mg) on the mechanical properties of resistance arteries in adult and old rats. Studies were performed in adult (17 weeks) and old (104 weeks) male Wistar rats. The vasodilatory response and the passive mechanical properties of the wall of isolated perfused and pressurized arterial segments of mesenteric small arteries were investigated after Mg and verapamil application, both known for their calcium antagonistic properties. Mesenteric resistance arteries from old rats exhibited an outward hypertrophic remodelling, with enlargment of the lumen, thickening of the media and enlarged media cross-sectional area. The vasodilatory response induced by the application of increasing extracellular concentrations of Mg and verapamil was significantly smaller in preconstricted mesenteric arteries of old rats than in those of adult rats. Incremental distensibility in response to increasing intravascular pressures did not change. However, the stress-strain curve was shifted to the left in pressurized mesenteric arteries from old rats, indicating arterial wall stiffness. Verapamil (3 micro mol/L) did not modify the stress-strain curves in either adult or aged rats. However, Mg (4.8 mmol/L) significantly shifted the curve to the right in mesenteric arteries from adult rats and, to a greater degree, in those from old rats. Although Mg-induced vasodilatation is impaired in aged rats, increased Mg concentration improved the mechanics of pressurized mesenteric resistance arteries. The fact that Mg decreases arterial stiffness in arteries from old rats suggests that Mg has a beneficial effect on age-related changes to the vascular wall.
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Affiliation(s)
- Mark Adrian
- Laboratoire Physiologie Pharmacologie et Nutrition Préventive Expérimentale, Besançon, France
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31
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Li J, Li W, Altura BT, Altura BM. Peroxynitrite-induced relaxation in isolated canine cerebral arteries and mechanisms of action. Toxicol Appl Pharmacol 2004; 196:176-82. [PMID: 15050419 DOI: 10.1016/j.taap.2003.12.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 12/11/2003] [Indexed: 11/21/2022]
Abstract
The present study was undertaken to determine the vascular actions of peroxynitrite (ONOO(-)), the product of superoxide and nitric oxide (NO), in isolated canine cerebral arteries and to gain insight into its potential mechanisms of action. In the absence of any vasoactive agent, ONOO(-) (from 10(-7) to 10(-6) M) was able to reduce the basal tension. In prostaglandin F2alpha-precontracted canine basilar arterial rings, ONOO(-) elicited concentration-dependent relaxation at concentrations from 10(-8) to 10(-5) M. The effective concentrations producing approximately 50% maximal relaxation (EC(50)) to ONOO(-) were 4.06 x 10(-6) and 4.12 x 10(-6) M in intact and denuded rings, respectively (P > 0.05). No significant differences in relaxation responses were found in ring preparations with or without endothelium (P > 0.05). The presence of either 5 microM methylene blue (MB) or 5 microM 1H-[1,2,4]oxadiazolo-[4,3-alpha]quinoxalin-1-one (ODQ) significantly inhibited the relaxations induced by ONOO(-). Tetraethylammonium chloride (T-2265) significantly decreased the ONOO(-)-induced relaxations in a concentration-dependent manner. However, ONOO(-) had no effect on rings precontracted by high KCL (P > 0.05). Addition of low concentrations of calyculin A (50 nM) was able to abolish the ONOO(-)-induced relaxation. Furthermore, ONOO(-) significantly inhibited calcium-induced contractions of K(+)-depolarized canine cerebral rings in a concentration-related manner. Lastly, a variety of pharmacological agents and antagonists including L-NMMA, l-arginine, indomethacin, atropine, naloxone, diphenhydramine, cimetine, glibenclamide, haloperidol, etc., did not influence the relaxant effects of ONOO(-) on the rings. Our new results suggest that ONOO(-)-triggered relaxation, on canine cerebral arteries, is mediated by elevation of cyclic guanosine monophosphate (cGMP) levels, membrane hyperpolarization via K+ channel activation, activation of myosin light chain phosphatase activity, and interference with calcium movement and cellular membrane Ca(2+) entry.
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Affiliation(s)
- Jianfeng Li
- Department of Physiology and Pharmacology, Downstate Medical Center, State University of New York, Brooklyn, NY 11203, USA
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32
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Berthon N, Laurant P, Fellmann D, Berthelot A. Effect of magnesium on mRNA expression and production of endothelin-1 in DOCA-salt hypertensive rats. J Cardiovasc Pharmacol 2003; 42:24-31. [PMID: 12827022 DOI: 10.1097/00005344-200307000-00004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The aim of this study was to investigate whether or not the decrease in blood pressure induced by dietary magnesium supplementation in DOCA-salt hypertensive rats is associated with modifications in expression and tissular production of endothelin-1. DOCA-salt treatment increased blood pressure, induced renal and cardiac hypertrophy, and increased endothelin-1 expression and production in the kidney, heart, and aorta. Mg supplementation for 8 weeks lowered blood pressure in DOCA-salt hypertensive rats and prevented hypertrophies and the increase of endothelin-1 expression and production in the heart, aorta, and kidney. Treatment with a receptor ETA antagonist, ABT-627, was used to clarify the relationship between the lowering effect of Mg supplementation on blood pressure and endothelin-1 production. When DOCA-salt rats were treated with ABT-627 for 8 weeks, Mg supplementation failed to lower blood pressure. In conclusion, these findings suggest that the lowering effect of Mg supplementation on blood pressure requires an inhibitory effect on endothelin-1 activity and/or endothelin-1 production in DOCA-salt hypertensive rats.
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Affiliation(s)
- Nathalie Berthon
- Laboratoire Physiologie, Pharmacologie et Nutrition Préventive Expérimentale, UFR Médecine et Pharmacie, Université de Franche-Comté, Besançon, France.
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Mauskop A, Altura BT, Altura BM. Serum ionized magnesium levels and serum ionized calcium/ionized magnesium ratios in women with menstrual migraine. Headache 2002; 42:242-8. [PMID: 12010379 DOI: 10.1046/j.1526-4610.2002.02075.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE It has been suggested that magnesium deficiency may play an important role in menstrual migraine and that the serum ionized calcium (ICa2+)/ionized magnesium (IMg2+) ratio is important in migraine headache. Studies were designed to test these hypotheses. DESIGN We prospectively evaluated 270 women seen at a headache clinic and in 61 women with menstrual migraine measured IMg2+, total magnesium, and ICa2+ levels so as to calculate the ICa2+/IMg2+ ratio. RESULTS The incidences of IMg2+ deficiency were 45% during menstrual attacks, 15% during nonmenstrual attacks, 14% during menstruation without a migraine, and 15% between menstruations and between migraine attacks. The serum ICa2+ levels were within our reference range, but the ICa2+/IMg2+ ratio was elevated (P<.01) in menstrual migraine. CONCLUSIONS The high incidence of IMg2+ deficiency and the elevated ICa2+/IMg2+ ratio during menstrual migraine confirm previous suggestions of a possible role for magnesium deficiency in the development of menstrual migraine.
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Affiliation(s)
- Alexander Mauskop
- New York Headache Center, SUNY Downstate Medical Center, Brooklyn 11203, USA
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34
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Yang Z, Wang J, Zheng T, Altura BT, Altura BM. Importance of extracellular Ca2+ and intracellular Ca2+ release in ethanol-induced contraction of cerebral arterial smooth muscle. Alcohol 2001; 24:145-53. [PMID: 11557300 DOI: 10.1016/s0741-8329(01)00145-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study was designed to investigate the roles of extracellular Ca2+ ([Ca2+]0) influx and intracellular free Ca2+ ([Ca2+]i) release in ethanol-induced contractions of isolated canine cerebral arteries and primary cultured, cerebral vascular smooth muscle cells. Ethanol (20-200 mM) produced significant contractions in isolated canine basilar arterial rings in a concentration-dependent manner. Removal of [Ca2+]0 and pretreatment of canine basilar arterial rings with verapamil (an antagonist of voltage-gated Ca2+ channels), thapsigargin (a selective antagonist of the sarcoplasmic reticulum Ca2+ pump), caffeine plus ryanodine (a specific antagonist of ryanodine-sensitive Ca2+ release), or heparin (an inositol 1,4,5,-trisphosphate [InsP3]-mediated Ca2+ release antagonist) markedly attenuated (approximately 50%-80%) ethanol-induced contractions. The absence of [Ca2+]0 and preincubation of primary single smooth muscle cells obtained from canine basilar arteries with verapamil, thapsigargin, heparin, or caffeine plus ryanodine markedly attenuated (approximately 50%-80%) the transient and sustained elevations in [Ca2+]i induced by ethanol. Results of the present study suggest to us that both Ca2+ influx through voltage-gated Ca2+ channels and Ca2+ release from intracellular stores (both InsP3 sensitive and ryanodine sensitive) are required for ethanol-induced contractions of isolated canine basilar arteries.
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Affiliation(s)
- Z Yang
- Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, NY 11203, USA
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35
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Yang ZW, Wang J, Zheng T, Altura BT, Altura BM. Importance of PKC and PI3Ks in ethanol-induced contraction of cerebral arterial smooth muscle. Am J Physiol Heart Circ Physiol 2001; 280:H2144-52. [PMID: 11299216 DOI: 10.1152/ajpheart.2001.280.5.h2144] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the relationships of two potential intracellular signaling pathways, protein kinase C (PKC) and phosphatidylinositol 3-kinases (PI3Ks), to ethanol-induced contractions in cerebral arteries. Ethanol (20-200 mM) induces concentration-dependent constriction in isolated canine basilar arteries that is inhibited in a concentration-dependent manner by pretreatment of these vessels with 10(-9)-10(-3) M Gö-6976 (an antagonist selective for PKC-alpha and PKC-betaI), 10(-10)-10(-4) M bisindolylmaleimide I (a specific antagonist of PKC), and 10(-10)-10(-4) M wortmannin or 10(-8)-10(-2) M LY-294002 (selective antagonists of PI3Ks). Ethanol-induced increases in intracellular Ca(2+) concentration (from approximately 100 to approximately 500 nM) in canine basilar smooth muscle cells are also suppressed markedly (approximately 20-70%) in the presence of a similar concentration range of Gö-6976, bisindolymaleimide I, wortmannin, or LY-294002. This study suggests that activation of PKC isoforms and PI3Ks appears to be an important signaling pathway in ethanol-induced vasoconstriction of cerebral blood vessels.
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Affiliation(s)
- Z W Yang
- Department of Physiology and Pharmacology, Health Science Center at Brooklyn, State University of New York, Brooklyn, New York 11203, USA
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36
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Omu AE, Al-Bader AA, Dashti H, Oriowo MA. Effect of extracellular Mg concentration on electrically induced contractions of rat vas deferens in vitro. ARCHIVES OF ANDROLOGY 2001; 46:159-67. [PMID: 11339640 DOI: 10.1080/01485010151096388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Contraction of smooth muscles of the vas deferens plays an important role in the propulsion of sperm into the pelvic urethra. This study examined the influence of external Mg2+ concentration on reactivity of the rat vas deferens to electrical stimulation in vitro. Vasa deferentia isolated from adult male rats were set up in tissue baths containing physiological salt solution at 37 degrees C and were stimulated electrically. Thereafter, increasing concentrations of Mg2+ were added to the bath and their effects on electrically evoked contractions were recorded. The effect of external Mg2+ depletion on evoked contractions was also examined. External Mg2+ depletion enhanced the contractile response to electrical stimulation while increasing external Mg2+ concentration inhibited the contractions. The inhibitory effect of Mg2+ was partially reversed by increasing extracellular Ca2+ concentration and was not additive with nifedipine. The results indicate that reactivity of the vas deferens to electrical stimulation is modulated by extracellular Mg2+ concentration. The possible relevance of these data to sperm transport through the vas deferens is discussed.
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Affiliation(s)
- A E Omu
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Kuwait University, Safat
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37
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Touyz RM, Mercure C, Reudelhuber TL. Angiotensin II type I receptor modulates intracellular free Mg2+ in renally derived cells via Na+-dependent Ca2+-independent mechanisms. J Biol Chem 2001; 276:13657-63. [PMID: 11278387 DOI: 10.1074/jbc.m008101200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Treatment of Madin-Darby canine kidney (MDCK) cells with the peptide hormone angiotensin II (Ang II) results in an increase in the concentrations of cytosolic free calcium ([Ca(2+)](i)) and sodium ([Na(+)](i)) with a concomitant decrease in cytosolic free Mg(2+) concentration ([Mg(2+)](i)). In the present study we demonstrate that this hormone-induced decrease in [Mg(2+)](i) is independent of [Ca(2+)](i) but dependent on extracellular Na(+). [Mg(2+)](i), [Ca(2+)](i), and [Na(+)](i) were measured in Ang II-stimulated MDCK cells by fluorescence digital imaging using the selective fluoroprobes mag-fura-2AM, fura-2AM, and sodium-binding benzofuran isophthalate (acetoxymethyl ester), respectively. Ang II decreased [Mg(2+)](i) and increased [Na(+)](i) in a dose-dependent manner. These effects were inhibited by irbesartan (selective AT(1) receptor blocker) but not by PD123319 (selective AT(2) receptor blocker). Imipramine and quinidine (putative inhibitors of the Na(+)/Mg(2+) exchanger) and removal of extracellular Na(+) abrogated Ang II-mediated [Mg(2+)](i) effects. In cells pretreated with thapsigargin (reticular Ca(2+)-ATPase inhibitor), Ang II-stimulated [Ca(2+)](i) transients were attenuated (p < 0.01), whereas agonist-induced [Mg(2+)](i) responses were unchanged. Clamping the [Ca(2+)](i) near 50 nmol/liter with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) inhibited Ang II-induced [Ca(2+)](i) increases but failed to alter Ang II-induced [Mg(2+)](i) responses. Benzamil, a selective blocker of the Na(+)/Ca(2+) exchanger, inhibited [Na(+)](i) but not [Mg(2+)](i) responses. Our data demonstrate that in MDCK cells, AT(1) receptors modulate [Mg(2+)](i) via a Na(+)-dependent Mg(2+) transporter that is not directly related to [Ca(2+)](i). These data support the notion that rapid modulation of [Mg(2+)](i) is not simply a result of Mg(2+) redistribution from intracellular buffering sites by Ca(2+) and provide evidence for the existence of a Na(+)-dependent, hormonally regulated transporter for Mg(2+) in renally derived cells.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Adrenergic Uptake Inhibitors/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Amiloride/analogs & derivatives
- Amiloride/pharmacology
- Angiotensin II/pharmacology
- Animals
- Antihypertensive Agents/pharmacology
- Benzofurans/pharmacology
- Biphenyl Compounds/pharmacology
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Cell Line
- Cells, Cultured
- Chelating Agents/pharmacology
- Cytosol/metabolism
- Dogs
- Dose-Response Relationship, Drug
- Egtazic Acid/analogs & derivatives
- Egtazic Acid/pharmacology
- Ethers, Cyclic/pharmacology
- Fluorescent Dyes/pharmacology
- Fura-2/analogs & derivatives
- Fura-2/pharmacology
- Imidazoles/pharmacology
- Imipramine/pharmacology
- Irbesartan
- Kidney/metabolism
- Kinetics
- Magnesium/metabolism
- Microscopy, Fluorescence
- Peptides/pharmacology
- Pyridines/pharmacology
- Quinidine/pharmacology
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/physiology
- Sodium/metabolism
- Sodium/pharmacology
- Tetrazoles/pharmacology
- Time Factors
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Affiliation(s)
- R M Touyz
- Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Montreal, Quebec H2W 1R7, Canada.
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Altura BM, Zhang A, Cheng TP, Altura BT. Extracellular magnesium regulates nuclear and perinuclear free ionized calcium in cerebral vascular smooth muscle cells: possible relation to alcohol and central nervous system injury. Alcohol 2001; 23:83-90. [PMID: 11331105 DOI: 10.1016/s0741-8329(00)00131-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Quantitative digital imaging microscopy, confocal laser scanning microscopy (CLSM), and multiple molecular fluorescent probes were utilized to test the hypothesis that cerebral vascular muscle cell nuclear ([Ca(2+)](n)), perinuclear ([Ca(2+)](pn)), and cytoplasmic free calcium ([Ca(2+)](i)) levels are regulated by the concentration of extracellular free magnesium ions ([Mg(2+)](o)). Primary cultured canine cerebral vascular smooth muscle cells were loaded with either fura-2/AM, indo-1/AM, or fluo-3/AM, and the subcellular Ca(2+) responses to stepwise reduction in [Mg(2+)](o) (i.e., from 1.36 to 0.17 mM) were analyzed over time. With normal 1.36 mM [Mg(2+)](o)-containing incubation media, basal mean [Ca(2+)](i) was 89.6+/-15 nM. Lowering [Mg(2+)](o) to 1.07, 0.88, 0.48, and 0.17 mM resulted in rapid (<4 min) increments in [Ca(2+)](i) going to 213+/-43, 368+/-67, 471+/-77, and 642+/-98 nM, respectively; the longer the exposure time (up to 30 min) to lowered [Mg(2+)](o), the higher the [Ca(2+)](i). Restoration of [Mg(2+)](o) to normal caused decreases in [Ca(2+)](i) to 215.9+/-42.3 nM, but only complete removal of [Ca(2+)](o) returned [Ca(2+)](i) to basal levels. Results show that basal [Ca(2+)](pn) (282+/-92 nM) exceeds basal cytoplasmic Ca(2+) (61+/-27.8 nM) and [Ca(2+)](n) (20+/-7.6 nM). However, reduction of normal [Mg(2+)](o) to 0.48 mM resulted in dramatic, rapid rises in all subcellular compartments, where [Ca(2+)](pn) (1503+/-102 nM)>cytoplasmic Ca(2+) (688+/-49 nM) approximately equal to [Ca(2+)](n) (674+/-12 nM). Nuclear Ca(2+) rose dramatically (e.g., 35-40 times basal levels). Both verapamil (1 microM) and Ni(2+) (5 mM) prevented, completely, the rises in Ca(2+) in all compartments, suggesting that Mg(2+)-dependent Ca(2+) accumulation may be dependent on nuclear, endoplasmic reticulum-Golgi, and cytoplasmic L-type voltage membrane-regulated Ca(2+) channels. The normally low [Ca(2+)](n) suggests that Ca(2+) does not transport passively across the nuclear membrane in cerebral vascular smooth muscle cells. These results may help to explain much of the impact of hypomagnesemic states on cerebral-central nervous system pathobiology, and, particularly, alcohol-induced strokes.
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MESH Headings
- Alcoholism/metabolism
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cells, Cultured
- Cerebral Cortex
- Cytoplasm/drug effects
- Cytoplasm/metabolism
- Dogs
- Dose-Response Relationship, Drug
- Golgi Apparatus/drug effects
- Golgi Apparatus/metabolism
- Magnesium/pharmacology
- Magnesium/physiology
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Stroke/metabolism
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Affiliation(s)
- B M Altura
- Department of Physiology, Health Science Center, State University of New York at Brooklyn, Brooklyn, NY 11203, USA
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39
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Li W, Zheng T, Altura BM, Altura BT. Sex steroid hormones exert biphasic effects on cytosolic magnesium ions in cerebral vascular smooth muscle cells: possible relationships to migraine frequency in premenstrual syndromes and stroke incidence. Brain Res Bull 2001; 54:83-9. [PMID: 11226717 DOI: 10.1016/s0361-9230(00)00428-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinically, it is known that: (1) magnesium (Mg) supplementation relieves premenstrual problems (e.g., migraine, bloating and edema) occurring in the late luteal phase of the menstrual cycle; and (2) migraine syndromes, particularly in women, are associated with deficits in brain and serum ionized Mg levels. We investigated whether concentrations of sex steroid hormones, found in the serum during the menstrual cycle of women, are associated with changes in the levels of cytosolic free magnesium ions ([Mg2+]i in single cultured canine cerebral vascular smooth muscle cells. The resting level of [Mg2+]i in these cells was 645 +/- 89 microM before exposure to sex steroid hormones. Exposure of these vascular cells to a low concentration of estrogen (10 pg/ml) failed to interfere with the levels of [Mg2+]i. However, exposure to estrogen, at concentrations ranging from 40 to 200 pg/ml, induced significant loss of [Mg2+]i in a concentration-dependent manner. At a concentration of 200 pg/ml estrogen, the level of [Mg2+]i decreased approximately 30% in comparison with controls. Progesterone produced biphasic effects on the levels of [Mg2+]i, depending on its concentration. Exposure of the cultured cells to a low concentration of progesterone (0.5 ng/ml) resulted in an increased level of [Mg2+]i (from 690 +/- 50 microM to 753 +/- 56 microM, p < 0.05). However, when these cells were exposed to higher concentrations of progesterone (i.e., from 5.0 to 20 ng/ml), the cellular levels of [Mg2+]i were decreased significantly. The higher the estrogen or progesterone concentration, the lower the levels of [Mg2+]i. In contrast, testosterone, a male hormone, didn't produce any significant alteration in [Mg2+]i levels in these cerebral vascular smooth muscle cells. These data indicate that low, physiological concentrations of female sex hormones, estrogen and progesterone, help cerebral vascular smooth cells sustain normal concentrations of [Mg2+]i, which are beneficial to vascular function, whereas high levels of estrogen and progesterone deplete, significantly, [Mg2+]i in cerebral vascular smooth muscle cells, possibly resulting in cerebrovasospasms and reduced cerebral blood flows related to premenstrual syndromes, migraine and stroke risk. Our findings could provide new insight into the mechanism whereby migraine occurs frequently in the late luteal phase in the premenstrual syndrome. In addition, our results demonstrate that female sex steroids but not testosterone (in physiologic concentrations) can exert direct effects on [Mg2+]i in cerebral vascular cells.
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Affiliation(s)
- W Li
- Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, Brooklyn, NY 11203, USA
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40
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Yang ZW, Wang J, Zheng T, Altura BT, Altura BM. Low [Mg(2+)](o) induces contraction and [Ca(2+)](i) rises in cerebral arteries: roles of ca(2+), PKC, and PI3. Am J Physiol Heart Circ Physiol 2000; 279:H2898-907. [PMID: 11087246 DOI: 10.1152/ajpheart.2000.279.6.h2898] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Removal of extracellular Ca(2+) concentration ([Ca(2+)](o)) and pretreatment of canine basilar arterial rings with either an antagonist of voltage-gated Ca(2+) channels (verapamil), a selective antagonist of the sarcoplasmic reticulum Ca(2+) pump [thapsigargin (TSG)], caffeine plus a specific antagonist of ryanodine-sensitive Ca(2+) release (ryanodine), or a D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)]- mediated Ca(2+) release antagonist (heparin) markedly attenuates low extracellular Mg(2+) concentration ([Mg(2+)](o))-induced contractions. Low [Mg(2+)](o)-induced contractions are significantly inhibited by pretreatment of the vessels with Gö-6976 [a protein kinase C-alpha (PKC-alpha)- and PKC-betaI-selective antagonist], bisindolylmaleimide I (Bis, a specific antagonist of PKC), and wortmannin or LY-294002 [selective antagonists of phosphatidylinositol-3 kinases (PI3Ks)]. These antagonists were also found to relax arterial contractions induced by low [Mg(2+)](o) in a concentration-dependent manner. The absence of [Ca(2+)](o) and preincubation of the cells with verapamil, TSG, heparin, or caffeine plus ryanodine markedly attenuates the transient and sustained elevations in the intracellular Ca(2+) concentration ([Ca(2+)](i)) induced by low-[Mg(2+)](o) medium. Low [Mg(2+)](o)-produced increases in [Ca(2+)](i) are also suppressed markedly in the presence of Gö-6976, Bis, wortmannin, or LY-294002. The present study suggests that both Ca(2+) influx through voltage-gated Ca(2+) channels and Ca(2+) release from intracellular stores [both Ins(1,4,5)P(3) sensitive and ryanodine sensitive] play important roles in low-[Mg(2+)](o) medium-induced contractions of isolated canine basilar arteries. Such contractions are clearly associated with activation of PKC isoforms and PI3Ks.
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Affiliation(s)
- Z W Yang
- Department of Physiology and Pharmacology, Health Science Center at Brooklyn, State University of New York, Brooklyn, New York 11203, USA
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41
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Laurant P, Touyz RM. Physiological and pathophysiological role of magnesium in the cardiovascular system: implications in hypertension. J Hypertens 2000; 18:1177-91. [PMID: 10994748 DOI: 10.1097/00004872-200018090-00003] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Attention is growing for a potential role of magnesium in the pathoetiology of cardiovascular disease. Magnesium modulates mechanical, electrical and structural functions of cardiac and vascular cells, and small changes in extracellular magnesium levels and/or intracellular free magnesium concentration may have significant effects on cardiac excitability and on vascular tone, contractility and reactivity. Thus, magnesium may be important in the physiological regulation of blood pressure whereas alterations in cellular magnesium metabolism could contribute to the pathogenesis of blood pressure elevation. Although most epidemiological and experimental studies support a pathological role for magnesium in the etiology and development of hypertension, data from clinical studies have been less convincing. Furthermore, the therapeutic value of magnesium in the management of essential hypertension is unclear. The present review discusses the molecular, biochemical, physiological and pharmacological roles of magnesium in the regulation of vascular function and blood pressure and introduces novel concepts relating to magnesium as a second messenger in intracellular signaling in cardiovascular cells. In addition, alterations in magnesium regulation in experimental and clinical hypertension and the potential antihypertensive therapeutic effects of magnesium are addressed.
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Affiliation(s)
- P Laurant
- Laboratoire Physiologie, Pharmacologie et Nutrition Prèventive Expérimentale, UFR Médecine et Pharmacie, Université de Franche-Comté, Besancon, France
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42
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Resnick LM, Oparil S, Chait A, Haynes RB, Kris-Etherton P, Stern JS, Clark S, Holcomb S, Hatton DC, Metz JA, McMahon M, Pi-Sunyer FX, McCarron DA. Factors affecting blood pressure responses to diet: the Vanguard study. Am J Hypertens 2000; 13:956-65. [PMID: 10981544 DOI: 10.1016/s0895-7061(00)01221-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
To study physiologic factors affecting the blood pressure (BP) response to nonpharmacologic maneuvers, fasting blood glucose, insulin, lipid and mineral levels, urinary mineral excretion, and the calcium regulating hormones parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D (1,25 (OH)2D) were measured in 71 unmedicated hypertensive (26 hypertensive only [HT], 45 hypertensive hyperlipidemic [HTHL]), and 87 normotensive hyperlipidemic (NTHL) control subjects before and during a 10-week multicenter, randomized controlled trial comparing a prepared meal plan (CCNW) with a self-selected diet (SSD) based on nutritionist counseling. Blood pressure fell to a greater extent in hypertensive versus normotensive subjects (-8+/-1/-5+/-1 v -2+/-1/-2+/-1 mm Hg, P < .0001/P < .0001), and on CCNW versus SSD diets (delta systolic BP [SBP]/delta diastolic BP [DBP], P = .033/P = .002). Diet-induced weight change was the strongest correlate of changes in BP (SBP: r = 0.360, P < .0001; DBP: r = 0.414, P < .0001), which, on multivariate analysis for deltaSBP, could partly be accounted for by diet-induced changes in fasting glucose (r = 0.215, P = .009) and cholesterol (r = 0.219, P = .006) levels. Independently of weight, diet-induced changes in SBP also were significantly related to concomitant changes in urinary excretion of potassium (r = -0.285, P = .001), magnesium (r = -0.254, P = .003), and calcium relative to sodium (r = -0.200, P = .021), but not to sodium per se; and to changes in serum potassium (r = -0.249, P = .002), phosphorus (r = -0.279, P = .001), PTH (r = 0.288, P = .0006), and 1,25 D (r = 0.202, P = .017). We conclude that the ability of diet to lower BP successfully may result from the additive contributions of multiple components. Independently of weight loss and the associated changes in circulating glucose and cholesterol, BP is influenced by the increasing provision of minerals such as potassium, magnesium, and calcium, perhaps by virtue of their suppressive effects on circulating vasoactive calcium regulating hormones.
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Affiliation(s)
- L M Resnick
- Hypertension Center, New York-Presbyterian Hospital/Cornell University Medical Center, New York 10021, USA
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43
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Zheng T, Li W, Wang J, Altura BT, Altura BM. Sphingomyelinase and ceramide analogs induce contraction and rises in [Ca(2+)](i) in canine cerebral vascular muscle. Am J Physiol Heart Circ Physiol 2000; 278:H1421-8. [PMID: 10775118 DOI: 10.1152/ajpheart.2000.278.5.h1421] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies were designed to investigate effects of neutral sphingomyelinase (N-SMase) and ceramide analogs as well as phosphorylcholine on vascular tone and Ca(2+) mobilization in isolated canine cerebral arterial smooth muscle. N-SMase (0.001-0.1 U/ml) provoked a gradual but sustained vasoconstriction of arterial rings in a concentration-related manner that was endothelium independent. Incubation of denuded arterial rings in Ca(2+)-free medium or pretreatment with verapamil in extracellular Ca(2+) resulted in a reduction of the N-SMase-evoked constriction. Exposure of arterial rings to 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid (BAPTA)-AM did not, however, result in a reduction of N-SMase-induced constriction. Both staurosporine and bisindolymaleimide I attenuated N-SMase-induced contractions to 66% and 72% of control, respectively. N-SMase caused gradual and sustained rises in intracellular Ca(2+) concentration ([Ca(2+)](i)) in primary cultured cerebral vascular smooth muscle cells. Pretreatment of these cultured cells with nimodipine and verapamil caused a steady decline in N-SMase-induced rises in [Ca(2+)](i). Exposure of the cells to Ca(2+)-free solution reversed the [Ca(2+)](i)-induced rise triggered by N-SMase to the resting baseline. Both C(8) and C(16) ceramide (10(-9)-10(-6) M), but not phosphorylcholine, constricted denuded canine arterial rings in a concentration-related manner and elevated [Ca(2+)](i). Our results suggest that the sphingomyelin-signaling pathway, via a probable release of ceramide molecules, may play an important role in regulation of cerebral arterial wall tone.
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Affiliation(s)
- T Zheng
- Department of Physiology, State University of New York, Health Science Center at Brooklyn, Brooklyn, New York 11203, USA
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44
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Zheng T, Li W, Wang J, Altura BT, Altura BM. Effects of neutral sphingomyelinase on phenylephrine-induced vasoconstriction and Ca(2+) mobilization in rat aortic smooth muscle. Eur J Pharmacol 2000; 391:127-35. [PMID: 10720644 DOI: 10.1016/s0014-2999(00)00045-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The sphingomyelin pathway is now recognized as an important signal transduction system regulating various cellular functions, in which activation of a neutral sphingomyelinase induced by various extracellular stimulants results in selective degradation of sphingomyelin, yielding bioactive lipid intermediates, ceramides and phosphorylcholine. In the present study, our emphasis has been to examine the effects of exogenous Mg(2+)-dependent neutral sphingomyelinase, in physiological and pathophysiological magnesium concentrations, on phenylephrine-induced vasomotor tone and on intracellular free Ca(2+)([Ca(2+)](i)) mobilization in vitro. Neutral sphingomyelinase (0.001-0.1 U/ml), alone, did not elicit any significant changes in either basal tension or resting levels of [Ca(2+)](i) in rat aortic smooth muscle; similar results were obtained with phosphorylcholine. However, neutral sphingomyelinase (0.001-0.1 U/ml) and C(2)-ceramide or ceramide-1-phosphate, but not phosphorylcholine, attenuated phenylephrine-induced contractions, in isolated rat aortic rings, in a concentration-related manner. The addition of extracellular magnesium in different concentrations (0, 0.3, 1.2, 2.4 mM) modulated the neutral sphingomyelinase-vasorelaxant action in a concentration-dependent manner. Neutral sphingomyelinase-evoked relaxation was only partially endothelium-dependent. Nitric oxide synthase inhibitors, N(G)-nitro-L-arginine (L-NNA) and L-N(G)-monomethyl-arginine (L-NMMA), an inhibitor of prostanoid synthesis (indomethacin), and pharmacologic amine antagonists, such as atropine, diphenhydramine, cimetidine, propranolol, and methysergide as well as an opiate antagonist, naloxone, all failed to attenuate or interfere with the vasorelaxant responses of neutral sphingomyelinase. Three different inhibitors of protein kinase C (i.e., staurosporine, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) or bisindolylmaleimide I), when used over a wide concentration range, also failed to interfere with the neutral sphingomyelinase-induced relaxations. Neutral sphingomyelinase inhibited the elevations in [Ca(2+)](i) in cultured rat aortic smooth muscle cells caused by phenylephrine. Our results suggest that a Mg(2+)-dependent sphingomyelin signaling pathway may play an important regulatory role in arterial wall tone.
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MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Calcium/metabolism
- Cells, Cultured
- Ceramides/pharmacology
- Cyclooxygenase Inhibitors/pharmacology
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- In Vitro Techniques
- Indomethacin/pharmacology
- Magnesium/physiology
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Nitric Oxide Synthase/antagonists & inhibitors
- Phenylephrine/antagonists & inhibitors
- Phenylephrine/pharmacology
- Protein Kinase C/antagonists & inhibitors
- Rats
- Rats, Wistar
- Sphingomyelin Phosphodiesterase/pharmacology
- Vasoconstrictor Agents/antagonists & inhibitors
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- T Zheng
- Department of Physiology, Health Science Center at Brooklyn, State University of New York, Brooklyn, NY 11203, USA
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45
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Li W, Zheng T, Wang J, Altura BT, Altura BM. Extracellular magnesium regulates effects of vitamin B6, B12 and folate on homocysteinemia-induced depletion of intracellular free magnesium ions in canine cerebral vascular smooth muscle cells: possible relationship to [Ca2+]i, atherogenesis and stroke. Neurosci Lett 1999; 274:83-6. [PMID: 10553943 DOI: 10.1016/s0304-3940(99)00683-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Homocysteine (HC) at concentrations of from 0.05 to 1.0 mM caused dose-dependent loss of [Mg2+]i in cultured cerebral vascular smooth muscle cells (VSMC), whereas cysteine and methionine (its metabolic products) failed to interfere with changes in [Mg2+]i. HC, methionine and cysteine did not produce any changes in [Ca2+]i. Lowering [Mg2+]o to 0.3 mM resulted in elevation of [Ca2+]i and loss of [Mg2+]i. Depletion of [Mg2+]i, induced by HC, was potentiated by low Mg2+. Preincubation of these cells with vitamin B6, vitamin B12, folic acid, alone, did not alter [Ca2+]i or [Mg2+]i. Likewise, concomitant addition of vitamin B6, vitamin B12, or folic acid, together with HC (1 mM) did not change the reduction in [Mg2+]i induced by HC. However, concomitant addition of HC and the three vitamins inhibited completely the loss of [Mg2+]i. Exposure of these cells to each vitamin, alone, or combination of the three vitamins failed to interfere with reduction in [Mg2+]i induced by low [Mg2+]i, but it did suppress the rise in [Ca2+]i. Interestingly, in the presence of low [Mg2+]o, the vitamin combination did not retard depletion of [Mg2+]i. The present findings are compatible with the hypothesis that an increased serum HC concentration causes abnormal metabolism of Mg2+ in cerebral VSMC, thus priming these cells for HC-induced atherogenesis, cerebral vasospasm and stroke. Our results suggest the need for the three B-vitamins, together with normal physiological levels of Mg2+, in order to prevent [Mg2+]i depletion and occlusive cerebral vascular diseases induced by homocysteinemia.
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Affiliation(s)
- W Li
- Department of Physiology, State University of New York, Health Science Center at Brooklyn, 11203, USA
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46
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Altura BM, Altura BT. Association of alcohol in brain injury, headaches, and stroke with brain-tissue and serum levels of ionized magnesium: a review of recent findings and mechanisms of action. Alcohol 1999; 19:119-30. [PMID: 10548155 DOI: 10.1016/s0741-8329(99)00025-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although there is general agreement that chronic ingestion of alcohol poses great risks for normal cardiovascular functions and peripheral-vascular homeostasis, a direct cause and effect between the real phenomena of alcohol-induced headache and risk of brain injury and stroke is not appreciated. "Binge drinking" of alcohol is associated with an ever-growing number of strokes and sudden death. It is becoming clear that alcohol ingestion can result in profoundly different actions on the cerebral circulation (e.g., vasodilation, vasoconstriction-spasm, vessel rupture), depending upon dose and physiologic state of host. Using rats, it has been demonstrated that acute, high doses of ethanol can result in stroke-like events concomitant with alterations in brain bioenergetics. We review recent in vivo findings obtained with 31P-NMR spectroscopy, optical reflectance spectroscopy, and direct in vivo microcirculatory studies on the intact brain. Alcohol-induced hemorrhagic stroke is preceded by a rapid fall in brain intracellular free magnesium ions ([Mg2+]i) followed by cerebrovasospasm and reductions in phosphocreatine (PCr)/ATP ratio, intracellular pH, and the cytosolic phosphorylation potential (CPP) with concomitant rises in deoxyhemoglobin (DH), mitochondrial reduced cytochrome oxidase aa3 (rCOaa3), blood volume, and intracellular inorganic phosphate (Pi). Using osmotic mini-pumps implanted in the third cerebral ventricle, containing 30% ethanol, it was found that brain [Mg2+]i is reduced 30% after 14 days; brain PCr fell 15%, whereas the CPP fell 40%. Such animals became susceptible to stroke from nonlethal doses of ethanol. Human subjects with mild head injury have been found to exhibit early deficits in serum ionized Mg (IMg2+); the greater the degree of early head injury (30 min-8 h), the greater and more profound the deficit in serum IMg2+ and the greater the ionized Ca (ICa2+) to IMg2+ ratio. Patients with histories of alcohol abuse or ingestion of alcohol prior to head injury exhibited greater deficits in IMg2+ (and higher ICa2+/IMg2+ ratios) and, unlike the subjects without alcohol, did not leave the hospital for at least several days. Women, for some unknown reason, exhibit a much higher incidence of morbidity and mortality from subarachnoid hemorrhage (SAH) than men. Data on 105 men and women with different types of stroke indicate that, on the average, a 20% deficit in serum IMg2+ is seen; total Mg (TMg) or blood pH is usually near normal. Women with SAH, however, exhibit much lower IMg2+ and higher ICa2+/IMg2+ ratios; the presence of ethanol in the blood is associated with even more depression in IMg2+ in SAH in women. It is possible that prior alcohol ingestion is, in large measure, responsible for a great deal of this unexplained higher incidence of SAH in women. It has recently been reported that the cyclical changes in estrogenic hormones appear to control the serum IMg2+ level in young women. A surge in estrogenic levels prior to SAH could thus precipitate, in part, the SAH. In other human studies, it has been shown that migraines and headache, dizziness, and hangover, which accompany ethanol ingestion, are associated with rapid deficits in serum IMg2+ but not in TMg. The former, and the alcohol-associated headache, can be ameliorated with IV administration of MgSO4. Premenstrual tension-headache (PTH) and its exacerbation by alcohol in women is also accompanied by deficits in IMg2+, and elevation in serum ICa2+/IMg2+; IV MgSO4 corrects the PTH and the serum deficit in IMg2+. Animal experiments show that IV Mg2+ can prevent alcohol-induced hemorrhagic stroke and the subsequent fall in brain [Mg2+]i, [PCr], pHi, and CPP. Other recent data indicate that alcohol-induced cellular loss of [Mg2+]i is associated with cellular Ca2+ overload and generation of oxygen-derived free radicals; chronic pretreatment with vitamin E prevents alcohol-induced vascular injury and pathology in the brain. (ABSTRACT TRUNCATED)
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Affiliation(s)
- B M Altura
- Department of Physiology, State University of New York, Health Science Center at Brooklyn, 11203, USA
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47
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Barbagallo M, Dominguez LJ, Resnick LM. Protective effects of captopril against ischemic stress: role of cellular Mg. Hypertension 1999; 34:958-63. [PMID: 10523391 DOI: 10.1161/01.hyp.34.4.958] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Magnesium (Mg) deficiency enhances tissue sensitivity to ischemic damage, an effect reversed not only by Mg, but also by sulfhydryl (SH)-containing compounds. We therefore created an in vitro model of red blood cell ischemia to investigate whether the protective effects of these compounds might be related to effects on intracellular free Mg (Mg(i)) content. (31)P-nuclear magnetic resonance (NMR) spectroscopy was used to measure the high-energy metabolites ATP and 2,3-diphosphoglycerate (DPG) and Mg(i) and inorganic phosphate (P(i)) levels in erythrocytes before and for 6 hours after progressive oxygen depletion in the presence or absence of SH-compounds, including captopril, N-acetyl-L-cysteine (NAC), penicillamine, and N-(2-mercaptopropionyl)-glycine (MPG). Under basal aerobic conditions, captopril increased Mg(i) in a dose- and time-dependent fashion (174.5+/-5.3 to 217.1+/-5.1 micromol/L, P<0. 05 at 100 micromol/L, 60 minutes). The SH compounds NAC, penicillamine, and MPG but not the non-SH compound enalaprilat also significantly raised Mg(i) in erythrocytes (P<0.05). With oxygen deprivation, a consistent decrease occurred in both ATP and 2,3-DPG levels associated with a rise in P(i) and in the P(i)/2,3-DPG ratio used as an index of high-energy metabolite depletion. Captopril, compared with control, retarded the rise in P(i) and reduced the P(i)/2,3-DPG ratio (P<0.008 and P<0.025 at 4 and 6 hours, respectively). Furthermore, the higher the initial Mg(i) and the greater the captopril-induced rise in Mg(i), the greater the metabolite-protective effect (r=0.799 and r=0.823, respectively; P<0. 01 for both). Altogether, the data suggest that Mg influences the cellular response to ischemia and that the ability of SH compounds such as captopril to ameliorate ischemic injury may at least in part be attributable to the ability of such compounds to increase cytosolic free Mg levels.
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Affiliation(s)
- M Barbagallo
- Institute of Internal Medicine and Geriatrics, University of Palermo, Italy.
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48
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Touyz RM, Schiffrin EL. Activation of the Na(+)-H+ exchanger modulates angiotensin II-stimulated Na(+)-dependent Mg2+ transport in vascular smooth muscle cells in genetic hypertension. Hypertension 1999; 34:442-9. [PMID: 10489391 DOI: 10.1161/01.hyp.34.3.442] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study investigated the role of the Na(+)-H+ exchanger (NHE) on angiotensin II (Ang II)-induced activation of Na(+)-dependent Mg2+ transport in vascular smooth muscle cells (VSMCs) from Wistar-Kyoto rats (WKY; n=20) and spontaneously hypertensive rats (SHR; n=20). Intracellular free concentrations of Mg2+ ([Mg2+]i) and Na+ ([Na+]i) and intracellular pH (pHi) were measured with the specific fluorescent probes mag-fura 2-AM, SBFI-AM, and BCECF-AM, respectively. Na+ dependency of Mg2+ transport was assessed in Na(+)-free buffer, and the role of the NHE was determined with the highly selective NHE blocker 5-(N-methyl-N-isobutyl) amiloride (MIA). Basal [Mg2+]i was lower in SHR than WKY (0.59+/-0.01 versus 0.71+/-0.01 mmol/L, P<0.05). Basal pHi and [Na+]i were not different between the 2 groups. Ang II dose dependently increased [Na+]i and pHi and decreased [Mg2+]i. Responses were significantly greater (P<0.05) in SHR versus WKY ([Na+]i E(max)=37.5+/-1.1 versus 33.7+/-1.9 mmol/L; pHi E(max)=7.35+/-0.04 versus 7.20+/-0.01; [Mg2+]i E(min)=0. 28+/-0.09 versus 0.53+/-0.02 mmol/L, SHR versus WKY). In Na(+)-free buffer, Ang II-elicited [Mg2+]i responses were inhibited. MIA (1 micromol/L) inhibited Ang II-stimulated responses in WKY and normalized responses in SHR ([Mg2+]i E(min)=0.49+/-0.02). Ang II-stimulated activation of NHE was significantly increased (P<0.05) in SHR (0.07+/-0.002 DeltapH(i)/s) compared with WKY (0.05+/-0.004 DeltapH(i)/s). These data demonstrate that in VSMCs [Mg2+]i regulation is Na+ dependent, that activation of NHE modulates Na(+)-Mg2+ transport, and that increased activity of NHE may play a role in altered Na(+)-dependent regulation of [Mg2+]i in SHR.
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Affiliation(s)
- R M Touyz
- Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Quebec, Canada.
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49
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Yang ZW, Altura BT, Altura BM. Low extracellular Mg2+ contraction of arterial muscle: role of protein kinase C and protein tyrosine phosphorylation. Eur J Pharmacol 1999; 378:273-81. [PMID: 10493103 DOI: 10.1016/s0014-2999(99)00474-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The effects of extracellular Mg2+ ion ([Mg2+]0) deficiency on basal tension of isolated rat aortae and rat aortic smooth muscle cell Ca2+ metabolism were investigated in the present study. The contractions of rat aortae induced by diverse concentrations of low [Mg2+]0 were potentiated, greatly, by removal of the endothelium or pre-incubation of intact rat aortic rings with L-N(G)-monomethyl-arginine (L-NMMA). [Mg2+]0 deficiency-induced contractions were inhibited, to different degrees, by pre-treatment of the vessels with low concentrations of Gö6976, bisindolymaleimide I, genistein or a combination of bisindolymaleimide I with genistein. IC50 levels found for these three agents were found to be not too different from Ki values for these drugs. Pre-treatment of rat aortic smooth muscle cells with Gö6976, bisindolymaleimide I, genistein or a combination of bisindolymaleimide I with genistein suppressed, significantly, or almost eliminated both the rapid and stable increments in [Ca2+]i induced by Mg2+-free medium. The present findings suggest that both protein kinase C and protein tyrosine phosphorylation appear to play important roles in Mg2+ deficiency-induced contractions of isolated rat aortic smooth muscle, most likely via phosphorylation of L-type Ca2+ channels.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Arteries/drug effects
- Arteries/physiology
- Calcium/metabolism
- Carbazoles/pharmacology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- Genistein/pharmacology
- In Vitro Techniques
- Indoles/pharmacology
- Magnesium/pharmacology
- Male
- Maleimides/pharmacology
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Phosphoproteins/metabolism
- Phosphorylation
- Phosphotyrosine/metabolism
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/physiology
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Rats
- Rats, Wistar
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Affiliation(s)
- Z W Yang
- Department of Physiology, State University of New York, Health Science Center at Brooklyn, 11203, USA
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50
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Zheng T, Li W, Wang J, Altura BT, Altura BM. C2-ceramide attenuates phenylephrine-induced vasoconstriction and elevation in [Ca2+]i in rat aortic smooth muscle. Lipids 1999; 34:689-95. [PMID: 10478926 DOI: 10.1007/s11745-999-0414-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In the present study, we examined the effects of cell-permeable C2-ceramide on contraction of aortic smooth muscle and intracellular free Ca2+ ([Ca2+]i). C2-ceramide (10(-7) to 10(-4) M) alone did not elicit any significant changes in either basal tension or resting levels of [Ca2+]i in rat aortic smooth muscle. However, C2-ceramide (10(-7) to 10(-4) M) attenuated phenylephrine-induced contractions in isolated rat aortic rings in a concentration-related manner, and inhibited elevations in [Ca2+]i in cultured rat aortic smooth muscle cells induced by phenylephrine. C2-ceramide-induced relaxation was found to be only slightly endothelium-dependent. However, nitric oxide inhibitors (L-NNA, L-NMMA), an inhibitor of prostanoid synthesis (indomethacin), an inhibitor of opiate actions, and several inhibitors of the pharmacologic actions of various vasoactive amines all failed to interfere with the vasorelaxant responses of C2-ceramide. Three different inhibitors of protein kinase C, when used in a wide concentration range, also failed to interfere with the ceramide-induced relaxations. Our results suggest that the sphingomyelin-signaling pathway may play an important regulatory role in arterial wall tone.
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Affiliation(s)
- T Zheng
- Department of Physiology, State University of New York, Health Science Center at Brooklyn 11203, USA
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