Abstract
Capillarity, O2 diffusion distances and fiber crosssectional growth were measured in the hearts of guinea pigs exposed early during growth to hypobaric hypoxia (P B=430 torr,PO2=90 torr). Twelve 5-week old males were maintained in a hypobaric chamber for 4–14 weeks. Their hearts were perfusion-fixed via the aorta with a 2.5% glutaraldehyde, 1% formaldehyde buffered solution; blocks were cut from left (LV) and right (RV) ventricles, post-fixed in OsO4, dehydrated and embedded in Spurr medium. Blocks were cut transversely to fiber orientation, 0.5 μm thick, stained with Toluidine Blue, and photographed at 400 x. Number and location of capillaries and fiber cross-sectional areas (FCSA) were scored from these photographs and from those of normoxic controls. Growth rates were similar for control and hypoxic guinea pigs. As animals grew, LV and RV weights increased linearly with body weight. Hypoxic guinea pigs had LV weights similar to controls but the RV showed varying degrees of hypertrophy. Control and hypoxic guinea pigs showed similar linear increases in FCSA with ventricular weight, suggesting that hypertrophy was due to increased FCSA. Capillary density (CD) decreased and capillary-to-fiber ratio (C∶F) increased with FCSA, and O2 diffusion distances lengthened in LV and RV of animals in both groups. CD and C∶F were higher and O2 diffusion distances were shorter in most hypoxic animals compared to controls. When RV hypertrophy was large (RV>0.7 g) and failure imminent, CD, C∶F and O2 diffusion distances were similar to controls suggesting that in these hearts oxygenation was impaired.
Similar content being viewed by others
References
Arias-Stella J, Recavarren S (1962) Right ventricular hypertrophy in native children living at high altitude. Am J Pathol 41:55–64
Astorri E, Chizzola A, Visioli O, Anversa P, Olivetti G, Vitali-Mazza L (1971) Right ventricular hypertrophy — a cytometric study on 55 human hearts. J Mol Cell Cardiol 2:99–110
Badeer HS (1973) Cardiomegaly at high altitudes: pathogenetic considerations. Aerospace Med 44:1173–1180
Banchero N, Kayar SR, Blake CI (1984) Factors involved in the elicitation of increased capillarity in muscle. Fed Proc 43:10–16
Barer GR, Bee D, Wach RA (1983) Contribution of polycythemia to pulmonary hypertension in simulated high altitude in rats. J Physiol 336:27–38
Bui MV, Banchero N (1980) Effects of chronic exposure to cold or hypoxia on ventricular weights and ventricular myoglobin concentrations in guinea pigs during growth. Pflügers Arch 385:155–160
Fuster V, Danielson MA, Robb RA, Broadbendt JC, Brown AL, Elveback LR (1977) Quantitation of left ventricular myocardial fiber hypertrophy and interstitial tissue in human hearts with chronically increased volume and pressure overload. Circulation 55:504–508
Henquell L, Odoroff Cl, Honig CR (1977) Intercapillary distance and capillary reserve in hypertrophied rat hearts beating in situ. Circ Res 41:400–408
Honig CR, Bourdeau-Martini J (1973) Role of oxygen in control of the coronary capillary reserve. Adv Exp Med Biol 39:55–71
Ishikawa S, Fattal GA, Popiewicz J, Wyatt JP (1972) Functional morphometry of myocardial fibers in cor pulmonale. Am Rev Respir Dis 105:358–367
Karnovsky MJ (1965) A formaldehyde-glutaraldehyde fixative of high osmolarity for use in electron microscopy. J Cell Biol 27:137A-138A
Kayar SR, Archer PG, Lechner AJ, Banchero N (1982) The closest individual method in the analysis of the distribution of capillaries. Microvasc Res 24:326–341
Kayar SR, Banchero N (1983) Distribution of capillaries and diffusion distances in guinea pig myocardium. Pflügers Arch 396:350–352
Lechner AF, Salvato VL, Banchero N (1980) Hematology in developing guinea pigs. I. Normal maturation. Comp Biochem Physiol 66A:537–540
Lund DD, Tomanek RJ (1980) The effects of chronic hypoxia on the myocardial cell of normotensive and hypertensive rats. Anat Rec 196:421–430
Manohar M, Thurmon JC, Tranquilli WJ, Devous MD, Theodorakis MC, Shawley RV, Feller DL, Benson JG (1981) Regional myocardial blood flow and coronary vascular reserve in unanesthetized young calves with severe concentric right ventricular hypertrophy. Circ Res 48:785–796
Murray PA, Baia H, Fishbein MC, Vatner SF (1979) Effects of experimental right ventricular hypertrophy on myocardial blood flow in conscious dogs. J Clin Invest 64:421–427
Olsen EGJ, Path FRC (1979) The pathology of cardiomyopathies. A critical analysis. Am Heart J 98:385–392
Penaloza D, Sime F, Banchero N, Gamboa R, Cruz J, Marticorena E (1963) Pulmonary hypertension in healthy men born and living at high altitudes. Am J Cardiol 11:150–157
Rakusan K (1971) Quantitative morphology of capillaries of the heart. Methods Achiev Exp Pathol 5:272:286
Rakusan K, Moravec J, Hatt PY (1980) Regional capillary supply in the normal and hypertrophied rat heart. Microvasc Res 20:319–326
Rakusan K, Turek Z, Kreuzer F (1981) Myocardial capillaries in guinea pigs native to high altitude (Junin, Peru, 4,105 m). Pflügers Arch 391:22–24
Remensnyder JP, Majno G (1968) Oxygen gradients in healing wounds. Am J Pathol 52:301–323
Roberts JT, Wearn JT (1941) Quantitative changes in the capillary-muscle relationship in human hearts during normal growth and hypertrophy. Am Heart J 21:617–633
Rotta A (1943) Peso del corazon y numero de capilares cardiacos en cobayos de differentes alturas. Revista Argent Cardiol 10:186–199
Sillau AH, Aquin L, Bui MV, Banchero N (1980a) Chronic hypoxia does not affect guinea pig skeletal muscle capillarity. Pflügers Arch 386:39–45
Sillau AH, Cueva S, Morales P (1980b) Pulmonary arterial hypertension in male and female chickens at 3,300 m. Pflügers Arch 386:269–275
Tomanek RJ, Searls JC, Lachenbuck PA (1982) Quantitative changes in the capillary bed during developing, peak, and stabilized cardiac hypertrophy in the spontaneously hypertensive rat. Circ Res 51:295–304
Tucker A, McMurtry IF, Reeves JT, Alexander AF, Will DH, Grover RF (1975) Lung vascular smooth muscle as a determinant of pulmonary hypertension at high altitude. Am J Physiol 228:762–767
Turek Z, Grandtner M, Kreuzer F (1972) Cardiac hypertrophy, capillary and muscle fiber density, muscle fiber diameter, capillary radius and diffusion distance in the myocardium of growing rats adapted to a simulated altitude of 3,500 m. Pflügers Arch 335:19–28
Turek Z, Grandtner M, Kubat K, Ringnalda BEM, Kreuzer F (1978) Arterial blood gases, muscle fiber diameter and intercapillary distance in cardiac hypertrophy of rats with an old myocardial infarction. Pflügers Arch 376:209–215
Valdivia E (1957) Right ventricular hypertrophy in guinea pigs exposed to simulated high altitude. Circ Res 5:612–616
Wearn JT (1941) Alterations in the heart accompanying growth and hypertrophy. Bull Johns Hopkins Hosp 68:363–374
Zerbe GO, Archer PG, Banchero N, Lechner AJ (1982) On comparing regression lines with unequal slopes. Am J Physiol 242 (Reg Intergrat Comp Physiol 11):R178-R180
Author information
Authors and Affiliations
Additional information
Supported by NIH grants HL-18145 and HL-28849
Supported by NIH Post Doctoral Fellowship HL-06527
Rights and permissions
About this article
Cite this article
Kayar, S.R., Banchero, N. Myocardial capillarity in acclimation to hypoxia. Pflugers Arch. 404, 319–325 (1985). https://doi.org/10.1007/BF00585342
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00585342