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Fetal origin of cardiovascular disease
Friday 14 October 1994: Workshop Abstracts W25 Promising advances and unrradirional views in atherorhrombosis research
348
W25 PROMISING
ADVANCES
AND UNTRADITIONAL RESEARCH
Fetal origin of cardiovascular disease &&&I&N, Barker DJP, MRC Environmental Epidemiology Unit (Univ. of Southampton), Southampron General Hosp., Southampton SO16 6YD, UK
A follow-up study of 1586 singleton boys born alive in the Jessop Hospital, Sheffield, England, during 1907-1924, who were measured in detail at birth showed that increased mortality from cardiovascular disease (ICD 9th revision codes 390-459) was related to reduced fetal growth. Standardized mortality ratios for cardiovascular disease fell from 119 in men who weighed 5.5 pounds or less at birth to 74 in men who weighed mom than 8.5 pounds @ = 0.02). Two farther studies of men and women born in the same hospital and still living in Sheffield have now been carried out. In 235 people now aged around 50 years, levels of systolic blood pressure and plasma concentrations of both LDL-cholesterol and fibrinogen were highest in people who had been small at birth. These relations were independent of duration of gestation and were unaffected by adjustment for current smoking, body mass index and alcohol consumption. In a study of 181 people aged around 70 years, prevalence of atheroma in the extra-cranial portion of the carotid arteries, as detected by duplex ultrasound imaging, was highest in those who had been light at birth. These findings suggest that reduced fetal growth is an important determinant of risk of vascular disease in adult life. Circulating cells of bone marrow origin and atherosclerosis Soboleva E, Popkova V, Saburova 0, Tararak E, WV, Inst. of Experimental Cardiol., Cardiol. Res. Center, 3rd Cherepkovskaya str., 15-A, Moscow 121552, Russia
Colony forming units (CFU) were found in cell cultures after placing into a semi-solid test system human aortic intima with various degrees of atherosclerosis. After 14-21 days, cultures of intimal cells produced hemopoietic and stromal colonies. Ultrastructural and histochemical analysis of these colonies demonstrated the presence, in addition to hemopoietic precursor cells (granulocyte/macrophages, basophil/mast cells), CFU-fibroblasts (Cm-f) with stroma-forming capacity able to form collagenproducing colonies in agar and osteoid matrix in liquid culture. Fibroblastoid precursor cells found in atherosclerotic intima are likely to originate from bone marrow. This is supported by the finding of CFU-f in peripheral blood of patients with pronounced atherosclerosis. Blood mononucleocytes from patients with primary hyperlipidemia (PI-IL) of IIa and IIb types and angiographitally documented coronary atherosclerosis were tested in systems similar to those used for demonstration of CFU in aotic intima. Applying histochemical, cytoimmunomorphological and ultrastructural approaches, we found stromal colonies on the 14th day under culture conditions in which cells synthesize in vitro extracellular fibrillar or osteoid matrix. Cells in these colonies stained positive with osteonectine. In patients with PHL the ratio of stromal colonies to total number of colonies grown in culture from blood mononucleocytes was high (44-85%), whereas in normolipidemic donors no growth of stmmal colonies was observed. The existence of hemopoietic precursor cells in intima suggests that at early stages of atherogenesis the microenvironment developed in the vascular wall is sufficient for ectopic hemopoiesis. Our data may provide a link between the appearance of circulating CFU-I in blood and atherosclerotic lesions in vessels in PHL. Role of the adventitia in atherogenesis w, King’s Coil. Sch. of Med. and Wellcome Research Labs., London SE5 9PJ, UK
VIEWS IN ATHEROTHROMBOSIS
Removal of the carotid artery adventitia from rabbits induced the formation of an intimal hyperplastic lesion. In rabbits fed a normal diet, the lesion (measured as the intimakmedial ratio) was maximal by day 14 (0.456 f 0.079, n = 5, P c O.Ol), and thereafter regressed towards control dimensions (0.037 f 0.003, n = 14) by day 28 (0.080 f 0.025, n = 7, P = 0.14). In rabbits fed a high cholesterol diet, the lesion was again maximal by day 14 (0.376 f 0.056, n = 8, P < 0.01). Although some regression was seen, the lesion persisted to day 42 (0.272 f 0.052, n = 8, P < 0.01). Electron microscopy and immunocytochemistry showed two types of lesion: (a) smooth muscle cell-predominant on normal diet and (b) macrophage-predominant on high cholesterol diet. Smooth muscle cell-predominant lesions underwent almost complete regression, whereas macrophage-predominant lesions persisted. It is proposed that lesion formation may be initiated following the development of arterial wall hypoxia, secondary to excision of the advent&d vasa vasorum. Furthermore, a novel method to restore a highly vascular ‘neoadventitia’ to an artery whose adventitia has previously been removed has been devised, using loosely placed PVC tubing. It is suggested this ‘neoadventitia’ was able to inhibit the formation of an intimal hyperplastic lesion and to promote regression of an aheady established lesion by restoring zuterial wall oxygenation. Determinants of LDL and fibrinogen uptake by artery walls Born GVF& The William Harvey Res. Inst., St. Bartholomew’s Hosp. Med. Coil.. Charferhouse UK
Square, London ECIM
6BQ,
Atherosclerosis is initiated by the uptake, modification and accumulation of LDL and fibrinogen in arterial intima. Abnormally high concentrations of circulating LDL are associated with prematnre clinical manifestation of atherosclerosis, indicating that LDL uptake increases with plasma concentration. Our experimental evidence indicates that uptake of these athemgenic proteins is also determined by other factors, as follows: (1) the density of anionic sites on the endothelial surface; (2) a process which is inhibited by the dihydropyridine calcium antagonists in large arteries and the microvasculature; (3) processes stimulated by noradrenaline, adrenaline, angiotensin II, or LNAME to inhibit nitric oxide formation, which may involve their blood pressureraising effect as well as other mechanisms. Heat shock proteins in atherosclerosis m, Zhu W, Roma P, Inst. of Pharmacol. Sci., Univ. of Milano, Via Balzaretti 9, 20133 Milano, Italy
In recent years much attention has been focused on the so-called ‘stress protein’ or heat shock proteins (hsp). These proteins play the role of chaperones in regulating the appropriate folding of cellular proteins. Furthermore, the heat shock proteins play a role in protecting cells from oxidative stress. The presence of Hsp has been reported in endothelial cells from atherosclerotic plaques, and autoantibodies to Hsp have been detected in subjects with cardiovascular disease. Oxidation of LDL, a key event in athemsclerotic processes, involves the production of reactive species, such as oxygen intermediates and organic radicals, which may trigger endothelium dysfunction. We investigated whether in vitro oxidized LDL (OxLDL), a model for in vivo oxidized LDL, can represent an oxidative stress to cultured endothelium and induce the expression of stress proteins. [3H]Adenine-release assay demonstrated that OxLDL (2OOpuglml)were cytotoxic to EAhy-926 endothelial cells when cultured in sparse conditions (52.4 f 7.10% vs. 21.3 f 0.42% with LDL and 20.2 f 0.85% with
Atherosclerosis X, Montreal, October 1994
348
W25 PROMISING
ADVANCES
AND UNTRADITIONAL RESEARCH
Fetal origin of cardiovascular disease &&&I&N, Barker DJP, MRC Environmental Epidemiology Unit (Univ. of Southampton), Southampron General Hosp., Southampton SO16 6YD, UK
A follow-up study of 1586 singleton boys born alive in the Jessop Hospital, Sheffield, England, during 1907-1924, who were measured in detail at birth showed that increased mortality from cardiovascular disease (ICD 9th revision codes 390-459) was related to reduced fetal growth. Standardized mortality ratios for cardiovascular disease fell from 119 in men who weighed 5.5 pounds or less at birth to 74 in men who weighed mom than 8.5 pounds @ = 0.02). Two farther studies of men and women born in the same hospital and still living in Sheffield have now been carried out. In 235 people now aged around 50 years, levels of systolic blood pressure and plasma concentrations of both LDL-cholesterol and fibrinogen were highest in people who had been small at birth. These relations were independent of duration of gestation and were unaffected by adjustment for current smoking, body mass index and alcohol consumption. In a study of 181 people aged around 70 years, prevalence of atheroma in the extra-cranial portion of the carotid arteries, as detected by duplex ultrasound imaging, was highest in those who had been light at birth. These findings suggest that reduced fetal growth is an important determinant of risk of vascular disease in adult life. Circulating cells of bone marrow origin and atherosclerosis Soboleva E, Popkova V, Saburova 0, Tararak E, WV, Inst. of Experimental Cardiol., Cardiol. Res. Center, 3rd Cherepkovskaya str., 15-A, Moscow 121552, Russia
Colony forming units (CFU) were found in cell cultures after placing into a semi-solid test system human aortic intima with various degrees of atherosclerosis. After 14-21 days, cultures of intimal cells produced hemopoietic and stromal colonies. Ultrastructural and histochemical analysis of these colonies demonstrated the presence, in addition to hemopoietic precursor cells (granulocyte/macrophages, basophil/mast cells), CFU-fibroblasts (Cm-f) with stroma-forming capacity able to form collagenproducing colonies in agar and osteoid matrix in liquid culture. Fibroblastoid precursor cells found in atherosclerotic intima are likely to originate from bone marrow. This is supported by the finding of CFU-f in peripheral blood of patients with pronounced atherosclerosis. Blood mononucleocytes from patients with primary hyperlipidemia (PI-IL) of IIa and IIb types and angiographitally documented coronary atherosclerosis were tested in systems similar to those used for demonstration of CFU in aotic intima. Applying histochemical, cytoimmunomorphological and ultrastructural approaches, we found stromal colonies on the 14th day under culture conditions in which cells synthesize in vitro extracellular fibrillar or osteoid matrix. Cells in these colonies stained positive with osteonectine. In patients with PHL the ratio of stromal colonies to total number of colonies grown in culture from blood mononucleocytes was high (44-85%), whereas in normolipidemic donors no growth of stmmal colonies was observed. The existence of hemopoietic precursor cells in intima suggests that at early stages of atherogenesis the microenvironment developed in the vascular wall is sufficient for ectopic hemopoiesis. Our data may provide a link between the appearance of circulating CFU-I in blood and atherosclerotic lesions in vessels in PHL. Role of the adventitia in atherogenesis w, King’s Coil. Sch. of Med. and Wellcome Research Labs., London SE5 9PJ, UK
VIEWS IN ATHEROTHROMBOSIS
Removal of the carotid artery adventitia from rabbits induced the formation of an intimal hyperplastic lesion. In rabbits fed a normal diet, the lesion (measured as the intimakmedial ratio) was maximal by day 14 (0.456 f 0.079, n = 5, P c O.Ol), and thereafter regressed towards control dimensions (0.037 f 0.003, n = 14) by day 28 (0.080 f 0.025, n = 7, P = 0.14). In rabbits fed a high cholesterol diet, the lesion was again maximal by day 14 (0.376 f 0.056, n = 8, P < 0.01). Although some regression was seen, the lesion persisted to day 42 (0.272 f 0.052, n = 8, P < 0.01). Electron microscopy and immunocytochemistry showed two types of lesion: (a) smooth muscle cell-predominant on normal diet and (b) macrophage-predominant on high cholesterol diet. Smooth muscle cell-predominant lesions underwent almost complete regression, whereas macrophage-predominant lesions persisted. It is proposed that lesion formation may be initiated following the development of arterial wall hypoxia, secondary to excision of the advent&d vasa vasorum. Furthermore, a novel method to restore a highly vascular ‘neoadventitia’ to an artery whose adventitia has previously been removed has been devised, using loosely placed PVC tubing. It is suggested this ‘neoadventitia’ was able to inhibit the formation of an intimal hyperplastic lesion and to promote regression of an aheady established lesion by restoring zuterial wall oxygenation. Determinants of LDL and fibrinogen uptake by artery walls Born GVF& The William Harvey Res. Inst., St. Bartholomew’s Hosp. Med. Coil.. Charferhouse UK
Square, London ECIM
6BQ,
Atherosclerosis is initiated by the uptake, modification and accumulation of LDL and fibrinogen in arterial intima. Abnormally high concentrations of circulating LDL are associated with prematnre clinical manifestation of atherosclerosis, indicating that LDL uptake increases with plasma concentration. Our experimental evidence indicates that uptake of these athemgenic proteins is also determined by other factors, as follows: (1) the density of anionic sites on the endothelial surface; (2) a process which is inhibited by the dihydropyridine calcium antagonists in large arteries and the microvasculature; (3) processes stimulated by noradrenaline, adrenaline, angiotensin II, or LNAME to inhibit nitric oxide formation, which may involve their blood pressureraising effect as well as other mechanisms. Heat shock proteins in atherosclerosis m, Zhu W, Roma P, Inst. of Pharmacol. Sci., Univ. of Milano, Via Balzaretti 9, 20133 Milano, Italy
In recent years much attention has been focused on the so-called ‘stress protein’ or heat shock proteins (hsp). These proteins play the role of chaperones in regulating the appropriate folding of cellular proteins. Furthermore, the heat shock proteins play a role in protecting cells from oxidative stress. The presence of Hsp has been reported in endothelial cells from atherosclerotic plaques, and autoantibodies to Hsp have been detected in subjects with cardiovascular disease. Oxidation of LDL, a key event in athemsclerotic processes, involves the production of reactive species, such as oxygen intermediates and organic radicals, which may trigger endothelium dysfunction. We investigated whether in vitro oxidized LDL (OxLDL), a model for in vivo oxidized LDL, can represent an oxidative stress to cultured endothelium and induce the expression of stress proteins. [3H]Adenine-release assay demonstrated that OxLDL (2OOpuglml)were cytotoxic to EAhy-926 endothelial cells when cultured in sparse conditions (52.4 f 7.10% vs. 21.3 f 0.42% with LDL and 20.2 f 0.85% with
Atherosclerosis X, Montreal, October 1994