關於研究重金屬含量與腦中風發生率相關性的文獻與佐證資料並不多，因此，本研究目的為探討與測量急性缺血性腦中風(acute ischemic stroke，AIS）病人血清與尿液中的重金屬「鉛（Pb）、汞（Hg）、砷（As）、鎘（Cd）」含量是否與急性缺血性腦中風有關係。我們選擇自急性缺血性腦中風發病日起算7日內且為第一次發生急性缺血性腦中風的病人作為實驗組，並選擇除高血壓外，沒有罹患過腦中風也沒有其它慢性疾病的健康人做為對照組。實驗組與對照組均接受抽血以檢驗體內重金屬含量，接著接受靜脈輸注1 g重金屬螯合劑 (Edetate Calcium Disodium, EDTA)以幫助體內重金屬自尿液排除，以蒐集24小時尿液檢體檢驗重金屬含量。共收案33例急性缺血性腦中風病人(實驗組)與39例健康人(對照組)，主要發現：一、實驗組尿液中鎘平均值與標準差較對照組高，兩組間有顯著統計意義（2.05 ± 2.17 vs. 1.22 ± 0.99 μg/L，P= 0.048）；二、實驗組血液中汞平均值較對照組低，兩組間有顯著統計意義（6.35 ± 4.26 vs. 9.76 ± 7.03 μg/L，P= 0.015）；實驗組尿液中汞平均值與標準差亦較對照組低，兩組間有顯著統計意義（1.31 ± 1.14 vs. 2.00 ± 1.16 μg/L，P= 0.013）。由此以上結果顯示，急性缺血性腦中風病人的尿鎘較健康人高，而血汞與尿汞則較健康人低，此項新的佐證發現體內重金屬含量與急性缺血性腦中風可能有相關性，但確切關係仍需進一步加以闡明。

Few studies examining the relationship between heavy metal amounts and stroke incidence have been reported. The aim of this study was to explore the relationship between heavy metal levels, including lead (Pb), mercury (Hg), arsenic (As) and cadmium (Cd), in patients with acute ischemic stroke (AIS). We selected patients with first-ever AIS onset within one week as our study group. Healthy controls were subjects without history of stroke or chronic disease, except hypertension. Patients and controls were initially studied to determine the serum level of Pb, Hg, As and Cd. All subjects received 1 gm infusion of edetate calcium disodium (EDTA). The urine specimen were collected for 24 hours after EDTA infusion and measured for the heavy metal levels. Thirty-three patients with AIS and 39 healthy controls were enrolled in this study. The major findings are: (1) The stroke group had a higher urine level of Cd compared to healthy control (2.05 ± 2.17 vs. 1.22 ± 0.99 μg/L, P= 0.048); (2) The stroke group had a lower serum level of Hg (6.35 ± 4.26 vs. 9.76 ± 7.03 μg/L, P= 0.015) and lower urine level of Hg (1.31 ± 1.14 vs. 2.00 ± 1.16 μg/L, P= 0.013) compared to healthy control. These findings indicate a higher level of urine Cd and lower levels of Hg in serum and urine of first-ever AIS patients, providing new evidence for potential association of dysregulated heavy metals in patients with AIS. Further studies are required to elucidate the roles of the identified heavy metals in the prevalence of AIS.

INTRODUCTION 1
STROKE 1
Thrombotic stroke 2
Embolic stroke 2
Hemorrhagic stroke 2
IMPORTANT FACTS ABOUT HEAVY METALS 3
Lead (Pb) 3
Mercury (Hg) 4
Arsenic (As) 6
Cadmium (Cd) 7
AIM OF THE STUDY 8
MATERIAL AND METHODS 9
STUDY DESIGN AND PARTICIPANTS 9
Inclusion Criteria 9
Exclusion Criteria 9
Study Procedures 10
DETERMINATION OF HEAVY METAL LEVELS 10
Edetate Calcium Disodium (EDTA) 10
Analytical Determinations 11
STATISTICAL ANALYSIS 13
RESULTS 14
DISCUSSION 16
CONCLUSION 19
ACKNOWLEDGEMENTS 19
DISCLOSURE STATEMENT 20
FIGURE 21
TABLES 22
REFERENCES 28
APPENDIX 34

[1] Feigin VL, Norrving B, Mensah GA. Global Burden of Stroke. Circ Res. 2017;120:439-48.
[2] Pennlert J, Eriksson M, Carlberg B, Wiklund PG. Long-term risk and predictors of recurrent stroke beyond the acute phase. Stroke. 2014;45:1839-41.
[3] Hsieh CY, Wu DP, Sung SF. Trends in vascular risk factors, stroke performance measures, and outcomes in patients with first-ever ischemic stroke in Taiwan between 2000 and 2012. J Neurol Sci. 2017;378:80-4.
[4] Kim YD, Jung YH, Saposnik G. Traditional Risk Factors for Stroke in East Asia. J Stroke. 2016;18:273-85.
[5] AHA/ASA. http://www.strokeassociation.org/STROKEORG/. 2017.
[6] Agency USEP. https://www.epa.gov/lead-air-pollution. 2017.
[7] Wikipedia. https://en.wikipedia.org/wiki/Lead. 2017.
[8] Kaji T. Cell biology of heavy metal toxicity in vascular tissue. Yakugaku zasshi : J Pharmaceut Soc Japan. 2004;124:113-20.
[9] Prozialeck WC, Edwards JR, Nebert DW, Woods JM, Barchowsky A, Atchison WD. The vascular system as a target of metal toxicity. Toxicol Sci. 2008;102:207-18.
[10] Linnamagi U, Kaasik AE. Changes of local cerebral blood flow concomitant to lead-exposure in adult rabbits. Acta neurologica Scand. 1995;92:491-6.
[11] Fujiwara Y, Kaji T, Yamamoto C, Sakamoto M, Kozuka H. Stimulatory effect of lead on the proliferation of cultured vascular smooth-muscle cells. Toxicology. 1995;98:105-10.
[12] Lee TH, Tseng MC, Chen CJ, Lin JL. Association of high body lead store with severe intracranial carotid atherosclerosis. Neurotoxicology. 2009;30:876-80.
[13] Bornschein RL, Succop P, Dietrich KN, Clark CS, Que Hee S, Hammond PB. The influence of social and environmental factors on dust lead, hand lead, and blood lead levels in young children. Environ Res. 1985;38:108-18.
[14] Basha CD, Reddy RG. Long-term changes in brain cholinergic system and behavior in rats following gestational exposure to lead: protective effect of calcium supplement. Interdiscipl Toxicol. 2015;8:159-68.
[15] Joy Mitra1 VV, Hegde1 PM, Boldogh I, Mitra1 S, Kent TA, Rao KS, Hegde1 ML. Revisiting metal toxicity in neurodegenerative diseases and stroke: Therapeutic Potential. Neurol Res Ther. 2014.
[16] Farina M, Avila DS, da Rocha JB, Aschner M. Metals, oxidative stress and neurodegeneration: a focus on iron, manganese and mercury. Neurochem Internat. 2013;62:575-94.
[17] Clarkson TW, Magos L, Myers GJ. The toxicology of mercury--current exposures and clinical manifestations. N Engl J Med. 2003;349:1731-7.
[18] Houston MC. Role of mercury toxicity in hypertension, cardiovascular disease, and stroke. J Clin Hypert (Greenwich, Conn). 2011;13:621-7.
[19] Sheehan MC, Burke TA, Navas-Acien A, Breysse PN, McGready J, Fox MA. Global methylmercury exposure from seafood consumption and risk of developmental neurotoxicity: a systematic review. Bull World Health Organ. 2014;92:254-69F.
[20] Lee CC, Chang JW, Huang HY, Chen HL. Factors influencing blood mercury levels of inhabitants living near fishing areas. Sci Environm. 2012;424:316-21.
[21] Carocci A, Rovito N, Sinicropi MS, Genchi G. Mercury toxicity and neurodegenerative effects. Rev Environment Contaminat Toxicol. 2014;229:1-18.
[22] Kim JH, Byun HM, Chung EC, Chung HY, Bae ON. Loss of integrity: impairment of the blood-brain barrier in heavy metal-associated ischemic stroke. Toxicol Res. 2013;29:157-64.
[23] Mutter J, Curth A, Naumann J, Deth R, Walach H. Does inorganic mercury play a role in Alzheimer's disease? A systematic review and an integrated molecular mechanism. J Alzheimers Dis. 2010;22:357-74.
[24] Kim YN, Kim YA, Yang AR, Lee BH. Relationship between blood mercury level and risk of cardiovascular diseases: results from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV) 2008-2009. Prevent Nutrit Food Sci. 2014;19:333-42.
[25] Agency USEP. https://www.epa.gov. 2016.
[26] Organization WH. http://www.who.int/mediacentre/factsheets/fs372/en/. 2016.
[27] Agency USEP. Terminology and Acronyms Report of Arsenic. 2012.
[28] Council NR. Arsenic in Drinking Water. Washington, DC: The National Academies Press; 1999.
[29] Wang CH, Hsiao CK, Chen CL, Hsu LI, Chiou HY, Chen SY, Hsueh YM, Wu MM, Chen CJ. A review of the epidemiologic literature on the role of environmental arsenic exposure and cardiovascular diseases. Toxicol Appl Pharmacol. 2007;222:315-26.
[30] Organization WH. Cadmium in Drinking-water. 2011.
[31] Fagerberg B, Barregard L, Sallsten G, Forsgard N, Ostling G, Persson M, Borne Y, Engstrom G, Hedblad B. Cadmium exposure and atherosclerotic carotid plaques--results from the malmo diet and cancer study. Environ Res. 2015;136:67-74.
[32] Messner B, Knoflach M, Seubert A, Ritsch A, Pfaller K, Henderson B, Shen YH, Zeller I, Willeit J, Laufer G, Wick G, Kiechl S, Bernhard D. Cadmium is a novel and independent risk factor for early atherosclerosis mechanisms and in vivo relevance. Arterioscler Thromb Vasc Biol. 2009;29:1392-8.
[33] Peters JL, Perlstein TS, Perry MJ, McNeely E, Weuve J. Cadmium exposure in association with history of stroke and heart failure. Environ Res. 2010;110:199-206.
[34] Wu MM, Chiou HY, Lee TC, Chen CL, Hsu LI, Wang YH, Huang WL, Hsieh YC, Yang TY, Lee CY, Yip PK, Wang CH, Hsueh YM, Chen CJ. GT-repeat polymorphism in the heme oxygenase-1 gene promoter and the risk of carotid atherosclerosis related to arsenic exposure. J Biomed Sci. 2010;17:70.
[35] Pharmacists. Edetate calcium disodium. https://www.drugs.com/mtm/edetate-calcium-disodium.html. 2017
[36] Ibad A, Khalid R, Thompson PD. Chelation therapy in the treatment of cardiovascular diseases. J Clinic Lipidol. 2016;10:58-62.
[37] Lamas GA, Ackermann A. Clinical evaluation of chelation therapy: is there any wheat amidst the chaff? Am Heart J. 2000;140:4-5.
[38] Lamas GA, Boineau R, Goertz C, Mark DB, Rosenberg Y, Stylianou M, Rozema T, Nahin RL, Terry Chappell L, Lindblad L, Lewis EF, Drisko J, Lee KL. EDTA chelation therapy alone and in combination with oral high-dose multivitamins and minerals for coronary disease: The factorial group results of the trial to assess chelation therapy. Am Heart J. 2014;168:37-44.e5.
[39] Knudtson ML, Wyse DG, Galbraith PD, Brant R, Hildebrand K, Paterson D, Richardson D, Burkart C, Burgess E. Chelation therapy for ischemic heart disease-A randomized controlled trial. JAMA. 2002;287:481-6.
[40] Green DJ, O’Driscoll JG, Maiorana A, Scrimgeour NB, Weerasooriya R, Taylor RR. Effects of chelation with EDTA and vitamin B therapy on nitric oxide-related endothelial vasodilator function. Clin Exp Pharmacol Physiol. 1999;26:853-6.
[41] Altun SK, Dinc H, Paksoy N, Temamogullari FK, Savrunlu M. Analyses of mineral content and heavy metal of honey samples from south and east region of Turkey by using ICP-MS. Int J Anal Chem. 2017;2017:6391454.
[42] Wikipedia. https://en.wikipedia.org/wiki/Inductively coupled plasma mass spectrometry. 2017.
[43] Thomas R. A Beginner’s Guide to ICP-MS. 2001.
[44] Bergdahl IA, Ahlqwist M, Barregard L, Bjorkelund C, Blomstrand A, Skerfving S, Sundh V, Wennberg M, Lissner L. Mercury in serum predicts low risk of death and myocardial infarction in Gothenburg women. Int Arch Occup Environ Health. . 2013;86:71-7.
[45] Chen YC, Chen MH. Mercury levels of seafood commonly consumed in Taiwan. JFDA. 2006;14:373-8.
[46] Plessi M, Davide B, Agar M. Mercury and selenium content in selected seafood. J Food Comp Anal. 2001;14:461-7.
[47] Navas-Acien A, Sharrett AR, Silbergeld EK, Schwartz BS, Nachman KE, Burke TA, Guallar E. Arsenic exposure and cardiovascular disease: a systematic review of the epidemiologic evidence. Am J Epidemiol. 2005;162:1037-49.