The purpose was to investigate the effects of artificial cold air on cardiovascular risk in hypertensive subjects. An artificial cold air was simulated with hourly ambient temperature data of a real moderate cold air in China. Twenty-four male SHR rats were randomly divided into the minimum temperature (Tmin) group, the rewarming temperature (Tr) group and two concurrent control groups with six rats in each (Tmin and Tr represent two cold air time points, respectively). Tmin and Tr groups were exposed to the cold air that was stopped at Tmin and Tr, respectively. After cold air exposure, blood pressure, heart rate and body weight were monitored, blood was collected for the detection of some indexes like fibrinogen, total cholesterol and uric acid. Results demonstrated that blood pressure, whole blood viscosity, blood fibrinogen, total cholesterol and uric acid increased significantly both in the Tmin and Tr groups; low density lipoprotein/high density lipoprotein increased significantly only in Tr group; there was higher level of blood fibrinogen in the Tr group than the Tmin group; higher levels of creatine kinase-MB was found in both the Tmin and Tr groups. These results suggest that cold air may increase the cardiovascular risks in hypertensive subjects indirectly through its effects on the sympathetic nervous system and renin angiotensin system, blood pressure and atherosclerosis risk factors like blood viscosity and fibrinogen, lipids and uric acid in the blood.
References
[1]
Hopstock, L.A.; Wilsgaard, T.; Njolstad, I.; Mannsverk, J.; Mathiesen, E.B.; Lochen, M.L.; Bonaa, K.H. Seasonal variation in incidence of acute myocardial infarction in a sub-arctic population: The tromso study 1974–2004. Eur. J. Cardiovasc. Prev. Rehabil. 2011, 18, 320–325, doi:10.1097/HJR.0b013e32833c7c28.
[2]
Danet, S.; Richard, F.; Montaye, M.; Beauchant, S.; Lemaire, B.; Graux, C.; Cottel, D.; Marecaux, N.; Amouyel, P. Unhealthy effects of atmospheric temperature and pressure on the occurrence of myocardial infarction and coronary deaths. A 10-year survey: The lille-world health organization monica project (monitoring trends and determinants in cardiovascular disease). Circulation 1999, 100, E1–E7.
[3]
Kriszbacher, I.; Koppan, M.; Bodis, J. Inflammation, atherosclerosis, and coronary artery disease. N. Engl. J. Med. 2005, 353, 429–430.
[4]
Neild, P.J.; Syndercombe-Court, D.; Keatinge, W.R.; Donaldson, G.C.; Mattock, M.; Caunce, M. Cold-induced increases in erythrocyte count, plasma cholesterol and plasma fibrinogen of elderly people without a comparable rise in protein C or factor X. Clin. Sci. (Lond.) 1994, 86, 43–48.
[5]
Woodhouse, P.R.; Khaw, K.T.; Plummer, M.; Foley, A.; Meade, T.W. Seasonal variations of plasma fibrinogen and factor vii activity in the elderly: Winter infections and death from cardiovascular disease. Lancet 1994, 343, 435–439.
[6]
Stout, R.W.; Crawford, V. Seasonal variations in fibrinogen concentrations among elderly people. Lancet 1991, 338, 9–13.
[7]
Keatinge, W.R.; Coleshaw, S.R.K.; Cotter, F.; Mattock, M.; Murphy, M.; Chelliah, R. Increases in platelet and red cell counts, blood viscosity, and arterial pressure during mild surface cooling: Factors in mortality from coronary and cerebral thrombosis in winter. Br. Med. J. (Clin. Res. Ed.) 1984, 289, 1405–1408.
[8]
Sun, Z. Cardiovascular responses to cold exposure. Front. Biosci. (Elite Ed.) 2010, 2, 495–503.
[9]
Watanabe, K.; Takahashi, T.; Miyajima, S.; Hirokawa, Y.; Tanabe, N.; Kato, K.; Kodama, M.; Aizawa, Y.; Tazawa, S.; Inoue, M. Myocardial sympathetic denervation, fatty acid metabolism, and left ventricular wall motion in vasospastic angina. J. Nucl. Med. 2002, 43, 1476–1481.
[10]
Luo, B.; Zhang, S.Y.; Ma, S.C.; Zhou, J.; Wang, B.J. Effects of cold air on cardiovascular disease risk factors in rat. Int. J. Environl. Res. Public Health 2012, 9, 2312–2325, doi:10.3390/ijerph9072312.
[11]
Qian, Z.M.; Koon, H.W. Area postrema is essential for the maintenance of normal blood pressure under cold stress in rats. Exp. Brain Res. 1998, 121, 186–190, doi:10.1007/s002210050451.
[12]
Tang, Z.Y.; Zhu, Q.Y.; Xu, L.J.; Deng, L.Y.; Zeng, Y.; Ding, W.J.; Huang, W. Artificial cold wave-induced cerebral infarction in rats with carotid atherosclerosis. J. Mol. Neurosci. 2012, 47, 278–285, doi:10.1007/s12031-012-9735-3.
[13]
Clauss, A. Rapid physiological coagulation method in determination of fibrinogen. Acta Haematol. 1957, 17, 237–246, doi:10.1159/000205234.
[14]
Sullivan, D.R.; Kruijswijk, Z.; West, C.E.; Kohlmeier, M.; Katan, M.B. Determination of serum triglycerides by an accurate enzymatic method not affected by free glycerol. Clin. Chem. 1985, 31, 1227–1228.
[15]
Nauck, M.; Warnick, G.R.; Rifai, N. Methods for measurement of LDL-cholesterol: A critical assessment of direct measurement by homogeneous assays versus calculation. Clin. Chem. 2002, 48, 236–254.
[16]
Warnick, G.R.; Nauck, M.; Rifai, N. Evolution of methods for measurement of HDL-cholesterol: From ultracentrifugation to homogeneous assays. Clin. Chem. 2001, 47, 1579–1596.
[17]
Siedel, J.; Hagele, E.O.; Ziegenhorn, J.; Wahlefeld, A.W. Reagent for the enzymatic determination of serum total cholesterol with improved lipolytic efficiency. Clin. Chem. 1983, 29, 1075–1080.
[18]
Gochman, N.; Schmitz, J.M. Automated determination of uric acid, with use of a uricase-peroxidase system. Clin. Chem. 1971, 17, 1154–1159.
[19]
Lipsitz, L.A.; Hamner, J.M.S.; Gagnon, M.; Babikian, V. Dynamic regulation of middle cerebral artery blood flow velocity in aging and hypertension. Stroke 2000, 31, 1897–1903, doi:10.1161/01.STR.31.8.1897.
[20]
Heijer, T.; Skoog, I.; Oudkerk, M.; de Leeuw, F.E.; de Groot, J.C.; Hofman, A.; Breteler, M.M. Associationbetween blood pressure levels over time and brain atrophy in the elderly. Neurobiol. Aging 2003, 24, 307–313.
[21]
Chobanian, A.V.; Alexander, R.W. Exacerbation of atherosclerosis by hypertension. Potential mechanisms and clinical implications. Arch. Intern. Med. 1996, 156, 1952–1956.
Mustard, J.F.; Murphy, E.A.; Ogryzlo, M.A.; Smythe, H.A. Blood coagulation and platelet economy in subjects with primary gout. Can. Med. Assoc. J. 1963, 89, 1207–1211.
[28]
Kang, D.H.; Nakagawa, T.; Feng, L.; Watanabe, S.; Han, L.; Mazzali, M.; Truong, L.; Harris, R.; Johnson, R.J. A role for uric acid in the progression of renal disease. J. Am. Soc. Nephrol. 2002, 13, 2888–2897, doi:10.1097/01.ASN.0000034910.58454.FD.
[29]
Watanabe, S.; Kang, D.H.; Feng, L.; Nakagawa, T.; Kanellis, J.; Lan, H.; Mazzali, M.; Johnson, R.J. Uric acid, hominoid evolution, and the pathogenesis of salt-sensitivity. Hypertension 2002, 40, 355–360.
[30]
Zhang, Y.; Hu, N.; Hua, Y.; Richmond, K.L.; Dong, F.; Ren, J. Cardiac overexpression of metallothionein rescues cold exposure-induced myocardial contractile dysfunction through attenuation of cardiac fibrosis despite cardiomyocyte mechanical anomalies. Free Radic. Biol. Med. 2012, 53, 194–207.
[31]
Morley, R.M.; Conn, C.A.; Kluger, M.J.; Vander, A.J. Temperature regulation in biotelemetered spontaneously hypertensive rats. Am. J. Physiol. 1990, 258, R1064–R1069.
[32]
Kirby, R.F.; Sokoloff, G.; Perdomo, E.; Blumberg, M.S. Thermoregulatory and cardiac responses of infant spontaneously hypertensive and Wistar-Kyoto rats to cold exposure. Hypertension 1999, 33, 1465–1469.
[33]
Hadjiisky, P.; Peyri, N. Hypertensive arterial disease and atherogenesis. Part. 1. Intimal changes in the old, spontaneously hypertensive rat (SHR). Atherosclerosis 1982, 44, 181–199, doi:10.1016/0021-9150(82)90113-7.
[34]
Yu, W.; Hu, W.; Mengersen, K.; Guo, Y.; Pan, X.; Connell, D.; Tong, S. Time course of temperature effects on cardiovascular mortality in Brisbane, Australia. Heart 2011, 97, 1089–1093.
[35]
Fernandez, M.L.; Webb, D. The LDL to HDL cholesterol ratio as a valuable tool to evaluate coronary heart disease risk. J. Am. Coll. Nutr. 2008, 27, 1–5.
[36]
Huynen, M.M.; Martens, P.; Schram, D.; Weijenberg, M.P.; Kunst, A.E. The impact of heat waves and cold spells on mortality rates in the Dutch population. Environ. Health Perspect. 2001, 109, 463–470, doi:10.1289/ehp.01109463.
[37]
Sun, Z.; Cade, J.R.; Fregly, M.J.; Rowland, N.E. Effect of chronic treatment with propranolol on the cardiovascular responses to chronic cold exposure. Physiol. Behav. 1997, 62, 379–384, doi:10.1016/S0031-9384(97)00033-4.
[38]
Sun, Z.; Cade, R.; Morales, C. Role of central angiotensin II receptors in cold-induced hypertension. Am. J. Hypertens. 2002, 15, 85–92, doi:10.1016/S0895-7061(01)02230-0.
[39]
Fujiwara, T.; Kawamura, M.; Nakajima, J.; Adachi, T.; Hiramori, K. Seasonal differences in diurnal blood pressure of hypertensive patients living in a stable environmental temperature. J. Hypertens. 1995, 13, 1747–1752.
[40]
Manfredini, R.; Gallerani, M.; Portaluppi, F.; Salmi, R.; Fersini, C. Chronobiological patterns of onset of acute cerebrovascular diseases. Thromb. Res. 1997, 88, 451–463, doi:10.1016/S0049-3848(97)00286-7.
[41]
Sun, Z.; Cade, R.; Katovich, M.J.; Fregly, M.J. Body fluid distribution in rats with cold-induced hypertension. Physiol. Behav. 1999, 65, 879–884.
[42]
Barney, C.C.; Katovich, M.J.; Fregly, M.J.; Tyler, P.E. Changes in beta-adrenergic responsiveness of rats during chronic cold exposure. J. Appl. Physiol. 1980, 49, 923–929.
