{"id":372,"date":"2023-12-04T10:24:37","date_gmt":"2023-12-04T15:24:37","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/chapter\/gross-anatomy-of-atherosclerosis\/"},"modified":"2023-12-04T10:46:47","modified_gmt":"2023-12-04T15:46:47","slug":"gross-anatomy-of-atherosclerosis","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/chapter\/gross-anatomy-of-atherosclerosis\/","title":{"raw":"Gross Anatomy and Histopathology of Atherosclerosis","rendered":"Gross Anatomy and Histopathology of Atherosclerosis"},"content":{"raw":"\n<div class=\"textbox textbox--learning-objectives\"><header class=\"textbox__header\">\n<p class=\"textbox__title\">Learning Objectives<\/p>\n\n<\/header>\n<div class=\"textbox__content\">\n\nBy the end of this chapter, you will be able to:\n<ul>\n \t<li>Identify macroscopic changes in the gross anatomy of the human aorta during different stages of atherosclerosis and its outcomes<\/li>\n \t<li>Relate key pathophysiological changes in the progression of atherosclerosis to the cell\/tissue changes visible on the histological slide<\/li>\n \t<li>Interpret lipid and elastin histological stains<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<h2>Stages of atherosclerosis (gross anatomy)<\/h2>\nIn this section, we will examine macroscopic changes that can occur in blood vessels of different sizes during atherosclerosis progression.\n<h3><strong>Early and moderate atherosclerosis&nbsp;<\/strong><\/h3>\n<div class=\"textbox\"><strong>Please note: <\/strong>the gross specimen of the aorta appears flat because the artery (physiologically a tube) has been cut open to expose the luminal (inner) side of the vessel. Here, we are looking at the [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary] - a place of atherosclerotic lesion initiation and a surface that physiologically in the human body is in direct contact with blood. Numerous openings on the aorta wall are origin sites of posterior intercostal arteries that branch off at this level of aorta and supply spine and rib cage with oxygenated blood.<\/div>\n&nbsp;\n<div class=\"textbox shaded\">\n\n<strong>Please note: <\/strong>the gross specimen of the aorta appears flat because the artery (physiologically a tube) has been cut open to expose the luminal (inner) side of the vessel. Here, we are looking at the [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary] - a place of atherosclerotic lesion initiation and a surface that physiologically in the human body is in direct contact with blood. Numerous openings on the aorta wall are origin sites of posterior intercostal arteries that branch off at this level of aorta and supply spine and rib cage with oxygenated blood.\n\n<strong>\nKey observations:&nbsp;<\/strong>\n\n<em><strong>Specimen A:<\/strong><\/em> mainly smooth [pb_glossary id=\"1033\"] intimal [\/pb_glossary] surface with early atherosclerotic lesions that appear as yellow cholesterol-containing plaques\/streaks. Poorly defined pearly grey discoloration near openings of intercostal arteries demonstrates connective tissue proliferation\n<em><strong>Specimen B<\/strong><\/em>: note the increased number and size of lesions compared to specimen A and the more irregular surface of the luminal side of the aorta\n\n<\/div>\n\n[caption id=\"attachment_4909\" align=\"aligncenter\" width=\"1280\"]<img class=\"wp-image-4909 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Early-Moderate-.png\" alt=\"Two specimens of aorta, cut so that the intimal space is visible. The left aorta is a relatively normal aorta with early changes with yellow\/orange\/white streaks on the relatively smooth intimal surface. The right aorta is an aorta with moderate atherosclerosis with more yellow\/orange\/white streaks but the surface is more bumpy\/shaggy\" width=\"1280\" height=\"720\"> <strong>Figure 8.30a \u2013 Early and moderate atherosclerosis of aorta<\/strong> DHPLC specimen C0324. All rights reserved[\/caption]\n<h3><strong>Severe and very severe atherosclerosis&nbsp;<\/strong><\/h3>\n<div class=\"textbox shaded\"><strong>Key observations\n<\/strong>\n<em><strong>Specimen C: <\/strong><\/em>Severe atherosclerosis. The wall of the aorta appears stiff and reduced in elasticity. The inner surface contained irregular nodules, patches, and streaks of atherosclerotic plaques that appear dirty yellow. Intima is absent in some areas, leaving surface ulcers. During specimen preparation, numerous calcium flecks were noticed, which rendered the vessel brittle.\n<em><strong>Specimen D: <\/strong><\/em>Very severe atherosclerosis. The aorta is rigid and inelastic, with its surface completely altered by atherosclerotic lesions in various stages. Multiple surface ulcers are present. The brownish-black patches demonstrate [pb_glossary id=\"1184\"]hemorrhage[\/pb_glossary] under the atherosclerotic plaques. Thrombosis is occurring over some of the ulcerated lesions. The rigidity is due to calcium deposition.<\/div>\n\n[caption id=\"attachment_4910\" align=\"aligncenter\" width=\"1280\"]<img class=\"wp-image-4910 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Severe-and-very-severe.png\" alt=\"Two specimens of aorta, cut so that the intimal space is visible. The left specimen is an aorta with severe atherosclerosis which is mostly white\/yellow streaks but the surface is bumpy\/shaggy. The right specimen is an aorta with severe atherosclerosis. The entire surface is bumpy, covered with multiple yellow\/orange plaques.\" width=\"1280\" height=\"720\"> <strong>Figure 8.30b Severe and very severe atherosclerosis of aorta.<\/strong> DHPLC Specimen C0330. All rights reserved.[\/caption]\n<h3>Histopathology of atherosclerosis<\/h3>\nWe will examine the histopathology of atherosclerosis using two slides of[pb_glossary id=\"1179\"] atheroma[\/pb_glossary] of the aorta coming from the same patient - a 65 y.o. man with a history of [pb_glossary id=\"1169\"]hypertension[\/pb_glossary] -&nbsp; one of the main risk factors of atherosclerosis.\n\nBoth slides are stained with special stains (fat stain and elastic tissue stain) that allow for visualization of specific tissue components that would not be clearly identifiable by the classic H&amp;E stain.\n\nWhile examining tissue slides, please note <em><strong>epithelial damage - <\/strong><\/em>&nbsp;an initial step of atherosclerosis progression that triggers subsequent inflammation and atherosclerotic plaque formation.\n\n&nbsp;\n\n[h5p id=\"184\"]\n<p style=\"background-color: #f0f0f0;padding: 5px;text-align: left\"><sup><strong>Histopathology of atherosclerosis (aorta)<\/strong> by Tetiana Povshedna licensed under CC BY 4.0 created with BioRender.com. Histology slides are DHPLC specimens PATH 425-032 (fat stain) and PATH 425-033 (elastin stain)<\/sup><\/p>\n&nbsp;\n<div class=\"textbox textbox--key-takeaways\"><header class=\"textbox__header\">\n<p class=\"textbox__title\">Fat Tissue Stain: Key Takeaways<\/p>\n\n<\/header>\n<div class=\"textbox__content\">\n<ul>\n \t<li>Irregularly thickened [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary] as a result of lipid accumulation<\/li>\n \t<li>Numerous lipid deposits in both [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary] and [pb_glossary id=\"1034\"]tunica media[\/pb_glossary]<\/li>\n<\/ul>\nOn a cellular level, this stage of atherosclerosis development is associated with the pro-inflammatory state, macrophage recruitment, and foam cell formation with subsequent necrotic core development.\n\n<\/div>\n<\/div>\n<div class=\"textbox textbox--key-takeaways\"><header class=\"textbox__header\">\n<p class=\"textbox__title\">Elastin Stain: Key Takeaways<\/p>\n\n<\/header>\n<div class=\"textbox__content\">\n<div class=\"textbox__content\">\n<ul>\n \t<li>Irregularly thickened [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary]; loss of elastic fibers in tunica intima (compare this elastic stain to an example of the normal human aorta in&nbsp; <a href=\"https:\/\/pressbooks.bccampus.ca\/pathology\/chapter\/normal-blood-vessel-anatomy-histology\/\">Gross anatomy and histology of normal aorta<\/a> and note the amount of elastic fibers in tunica intima)<\/li>\n \t<li>Elastic tissue appears compressed and fragmented in the superficial layers of [pb_glossary id=\"1034\"]tunica media[\/pb_glossary]. This fragmentation and weakening of the aorta wall might facilitate the formation of [pb_glossary id=\"1177\"]aneurysm&nbsp;[\/pb_glossary]<\/li>\n \t<li>On higher magnification, cholesterol crystals appear as stellate empty spaces in [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary]<\/li>\n \t<li>Areas of calcification appear as dark dense spots within tunica intima<\/li>\n<\/ul>\n<\/div>\nType your key takeaways here.\n<ul>\n \t<li>First<\/li>\n \t<li>Second<\/li>\n<\/ul>\n<\/div>\n<\/div>\n&nbsp;\n\nWhile all the histological slides and gross anatomy specimens above focused on various regions of aorta as a site of atherosclerotic plaque formation, coronary arteries are also one of the common and clinically relevant sites of atherosclerosis. Plaque formation within these arteries can cause [pb_glossary id=\"1152\"]hypoxia[\/pb_glossary] of the heart muscle which, if left untreated, can lead to a heart attack.\n\nThe video below examines the key features of atherosclerosis in [pb_glossary id=\"962\"]coronary arteries[\/pb_glossary]. Clinically, these changes would reflect the pathophysiology of ischemic heart disease.\n\n&nbsp;\n\n[h5p id=\"67\"]\n<p style=\"background-color: #f0f0f0;padding: 5px;text-align: left\"><sup><em><strong>Histopathology of atherosclerosis (coronary artery).<\/strong> Created and presented by Jonathan Bush.&nbsp; Histology slide is from private collection.&nbsp;<\/em><\/sup><\/p>\n\n<div><\/div>\n<div class=\"textbox shaded\">\n\nKey takeaways:\n<ul>\n \t<li>numerous immune cells in [pb_glossary id=\"1032\"]tunica externa [\/pb_glossary]reflect inflammatory process triggered by atherosclerosis<\/li>\n \t<li>a blood clot is obstructing the lumen, making tunica intima hard to identify<\/li>\n \t<li>fibrotic areas (appear pale pink and do not contain a lot of cell nuclei) reflect lipid accumulation<\/li>\n \t<li>foam cells that engulfed oxidized LDL&nbsp; in [pb_glossary id=\"1034\"]tunica media&nbsp;[\/pb_glossary]<\/li>\n<\/ul>\n<\/div>\n<h2>Clinical outcomes of severe atherosclerosis (gross anatomy)<\/h2>\n<h3><strong>Thrombosis of atherosclerotic aorta&nbsp;<\/strong><\/h3>\nThe formation of a clot is one of the common clinical outcomes of severe atherosclerosis. Thrombosis-induced [pb_glossary id=\"1153\"]ischemia [\/pb_glossary] can result in heart attack or stroke, depending on location. Clot formation as a result of atherosclerosis in coronary vessels can block the blood flow to the heart, and cause tissue damage as a result of [pb_glossary id=\"1152\"]hypoxia[\/pb_glossary]. Similar scenarios can occur anywhere along the vascular tree, including the brain (stroke), lower limb (peripheral artery disease), etc.\n\nThis specimen demonstrates a case of thrombosis in the abdominal aorta as a result of atherosclerosis.\n\n&nbsp;\n<div class=\"textbox shaded\">\n\n<strong>Patient history:&nbsp;<\/strong>\n\nAn elderly man with a history of peripheral artery disease - a manifestation of atherosclerosis in lower limbs, which resulted in bilateral leg amputation two years previously. Chief complaint on admission - pain. Cause of death - pneumonia; autopsy revealed generalized atherosclerosis.\n\nThe specimen demonstrates distal abdominal aorta as it divides into the right and left[pb_glossary id=\"1191\"] common iliac arteries[\/pb_glossary].\n\n<strong>Key observations: <\/strong>\n<ul>\n \t<li><em><strong>narrowing<\/strong><\/em> of the distal aorta by a dark thrombus which extends into common iliac arteries<\/li>\n \t<li><em><strong>thickening<\/strong> <\/em>of the aorta wall - numerous yellow atherosclerotic plaques that narrow the lumen<\/li>\n \t<li>typical<em><strong> location<\/strong> <\/em>of the plaque and thrombus - [pb_glossary id=\"1173\"]bifurcation[\/pb_glossary] of a large vessel where the [pb_glossary id=\"1171\"]laminar[\/pb_glossary] flow becomes [pb_glossary id=\"1172\"]turbulent[\/pb_glossary]<\/li>\n<\/ul>\n<\/div>\n\n[caption id=\"attachment_4911\" align=\"aligncenter\" width=\"1280\"]<img class=\"wp-image-4911 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Thrombosis-of-atherosclerotic-aorta.png\" alt=\"the abdominal aorta is cut open to reveal the inner intimal surface. On the left of the image, the proximal aorta shows yellow-white atherosclerotic plaques. In the middle of the image, the entire luminal space is filled with a dark blood thrombus (clot) centered around a shaggy atherosclerotic plaque with a needle-thin opening for blood. The right image shows the abdominal aorta splitting into the two common iliac arteries.\" width=\"1280\" height=\"720\"> <strong>Fig 8.31 Thrombosis of atherosclerotic aorta<\/strong>. DHPLC specimen C0414. All rights reserved[\/caption]\n\n&nbsp;\n<h3><strong>Aneurysm of atherosclerotic aorta&nbsp;<\/strong><\/h3>\nSevere atherosclerosis can progress towards [pb_glossary id=\"1177\"]aneurysm[\/pb_glossary], where the muscular layer of the vessel weakens and creates a bulge that can rupture and lead to internal bleeding.\n\nThis case demonstrates atherosclerotic aneurysm of the abdominal aorta.\n<div class=\"textbox shaded\">\n\n<strong>Patient history:&nbsp;<\/strong>\n\n75 y.o. man with a known abdominal aortic aneurysm, presented with [pb_glossary id=\"1181\"]epigastric[\/pb_glossary] pain for several days. Physical examination of abdomen revealed a non-painful mass about 10 cm in diameter. Aneurysm [pb_glossary id=\"1182\"]dissection[\/pb_glossary] was suspected. The autopsy revealed atherosclerosis of [pb_glossary id=\"1183\"]coronary[\/pb_glossary] vessels, as well as an atherosclerotic abdominal aneurysm with a thrombus.\n\n<strong>Key observations:&nbsp;&nbsp;<\/strong>\n<ul>\n \t<li>compare and contrast the diameter of abdominal aorta and aneurysm<\/li>\n \t<li>note numerous atherosclerotic plaques in the proximal part of the aorta<\/li>\n \t<li>the lumen of the aneurysm if partially filled with a mural thrombus<\/li>\n \t<li>typical location of atherosclerosis\/aneurysm - at the bifurcation of the abdominal aorta into right and left [pb_glossary id=\"1191\"]common iliac arteries[\/pb_glossary]<\/li>\n<\/ul>\n<strong>Compare and contrast the diameter of the abdominal aorta in the above figure and the one below of&nbsp;DHPLC specimens C0414 and C0309<\/strong>\n\n<\/div>\n\n[caption id=\"attachment_4912\" align=\"aligncenter\" width=\"1280\"]<img class=\"wp-image-4912 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Abdominal-aneurysm.png\" alt=\"The abdominal aorta is opened at the level of the aneurysm, exposing the inside. The aneurysm has many layers, like an onion, with a dark blood clot (thrombus) just off the centre. The bottom of the aorta shows the bifurcation to the common iliac arteries. The top of the image shows the abdominal aorta dotted with yellow white atherosclerotic plaques\" width=\"1280\" height=\"720\"> <strong>Fig 8.32. Atherosclerotic aneurysm of aorta<\/strong>. DHPLC specimen C0309 All rights reserved.[\/caption]\n<h1>Section review<\/h1>\nOn gross anatomy specimens, early atherosclerotic lesions appear as yellow streaks\/patches on the luminal side of the vessel. As the severity of atherosclerosis increases, atherosclerotic plaques grow in size and number and can cause ulceration. Advanced atherosclerotic vessels have an irregular luminal surface, numerous plaques, areas of calcification, ulceration, and clot formation. One of the most common clinical outcomes of advanced atherosclerosis is an aneurysm or clot formation.\n\nHistologically, lipid deposits are visible within the [pb_glossary id=\"1033\"] tunica intima[\/pb_glossary] and [pb_glossary id=\"1034\"]tunica media [\/pb_glossary] of atherosclerotic vessels. Endothelial damage, which is necessary for lesion initiation, is often present. During the advanced stages, cholesterol crystals and calcium deposits can be visualized in [pb_glossary id=\"1033\"]tunica intima[\/pb_glossary], while [pb_glossary id=\"1034\"]tunica media[\/pb_glossary] can appear fragmented.\n<h1>Review questions<\/h1>\n[h5p id=\"192\"]\n","rendered":"<div class=\"textbox textbox--learning-objectives\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Learning Objectives<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<p>By the end of this chapter, you will be able to:<\/p>\n<ul>\n<li>Identify macroscopic changes in the gross anatomy of the human aorta during different stages of atherosclerosis and its outcomes<\/li>\n<li>Relate key pathophysiological changes in the progression of atherosclerosis to the cell\/tissue changes visible on the histological slide<\/li>\n<li>Interpret lipid and elastin histological stains<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<h2>Stages of atherosclerosis (gross anatomy)<\/h2>\n<p>In this section, we will examine macroscopic changes that can occur in blood vessels of different sizes during atherosclerosis progression.<\/p>\n<h3><strong>Early and moderate atherosclerosis&nbsp;<\/strong><\/h3>\n<div class=\"textbox\"><strong>Please note: <\/strong>the gross specimen of the aorta appears flat because the artery (physiologically a tube) has been cut open to expose the luminal (inner) side of the vessel. Here, we are looking at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a> &#8211; a place of atherosclerotic lesion initiation and a surface that physiologically in the human body is in direct contact with blood. Numerous openings on the aorta wall are origin sites of posterior intercostal arteries that branch off at this level of aorta and supply spine and rib cage with oxygenated blood.<\/div>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">\n<p><strong>Please note: <\/strong>the gross specimen of the aorta appears flat because the artery (physiologically a tube) has been cut open to expose the luminal (inner) side of the vessel. Here, we are looking at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a> &#8211; a place of atherosclerotic lesion initiation and a surface that physiologically in the human body is in direct contact with blood. Numerous openings on the aorta wall are origin sites of posterior intercostal arteries that branch off at this level of aorta and supply spine and rib cage with oxygenated blood.<\/p>\n<p><strong><br \/>\nKey observations:&nbsp;<\/strong><\/p>\n<p><em><strong>Specimen A:<\/strong><\/em> mainly smooth <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\"> intimal <\/a> surface with early atherosclerotic lesions that appear as yellow cholesterol-containing plaques\/streaks. Poorly defined pearly grey discoloration near openings of intercostal arteries demonstrates connective tissue proliferation<br \/>\n<em><strong>Specimen B<\/strong><\/em>: note the increased number and size of lesions compared to specimen A and the more irregular surface of the luminal side of the aorta<\/p>\n<\/div>\n<figure id=\"attachment_4909\" aria-describedby=\"caption-attachment-4909\" style=\"width: 1280px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4909 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Early-Moderate-.png\" alt=\"Two specimens of aorta, cut so that the intimal space is visible. The left aorta is a relatively normal aorta with early changes with yellow\/orange\/white streaks on the relatively smooth intimal surface. The right aorta is an aorta with moderate atherosclerosis with more yellow\/orange\/white streaks but the surface is more bumpy\/shaggy\" width=\"1280\" height=\"720\" \/><figcaption id=\"caption-attachment-4909\" class=\"wp-caption-text\"><strong>Figure 8.30a \u2013 Early and moderate atherosclerosis of aorta<\/strong> DHPLC specimen C0324. All rights reserved<\/figcaption><\/figure>\n<h3><strong>Severe and very severe atherosclerosis&nbsp;<\/strong><\/h3>\n<div class=\"textbox shaded\"><strong>Key observations<br \/>\n<\/strong><br \/>\n<em><strong>Specimen C: <\/strong><\/em>Severe atherosclerosis. The wall of the aorta appears stiff and reduced in elasticity. The inner surface contained irregular nodules, patches, and streaks of atherosclerotic plaques that appear dirty yellow. Intima is absent in some areas, leaving surface ulcers. During specimen preparation, numerous calcium flecks were noticed, which rendered the vessel brittle.<br \/>\n<em><strong>Specimen D: <\/strong><\/em>Very severe atherosclerosis. The aorta is rigid and inelastic, with its surface completely altered by atherosclerotic lesions in various stages. Multiple surface ulcers are present. The brownish-black patches demonstrate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1184\">hemorrhage<\/a> under the atherosclerotic plaques. Thrombosis is occurring over some of the ulcerated lesions. The rigidity is due to calcium deposition.<\/div>\n<figure id=\"attachment_4910\" aria-describedby=\"caption-attachment-4910\" style=\"width: 1280px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4910 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Severe-and-very-severe.png\" alt=\"Two specimens of aorta, cut so that the intimal space is visible. The left specimen is an aorta with severe atherosclerosis which is mostly white\/yellow streaks but the surface is bumpy\/shaggy. The right specimen is an aorta with severe atherosclerosis. The entire surface is bumpy, covered with multiple yellow\/orange plaques.\" width=\"1280\" height=\"720\" \/><figcaption id=\"caption-attachment-4910\" class=\"wp-caption-text\"><strong>Figure 8.30b Severe and very severe atherosclerosis of aorta.<\/strong> DHPLC Specimen C0330. All rights reserved.<\/figcaption><\/figure>\n<h3>Histopathology of atherosclerosis<\/h3>\n<p>We will examine the histopathology of atherosclerosis using two slides of<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1179\"> atheroma<\/a> of the aorta coming from the same patient &#8211; a 65 y.o. man with a history of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1169\">hypertension<\/a> &#8211;&nbsp; one of the main risk factors of atherosclerosis.<\/p>\n<p>Both slides are stained with special stains (fat stain and elastic tissue stain) that allow for visualization of specific tissue components that would not be clearly identifiable by the classic H&amp;E stain.<\/p>\n<p>While examining tissue slides, please note <em><strong>epithelial damage &#8211; <\/strong><\/em>&nbsp;an initial step of atherosclerosis progression that triggers subsequent inflammation and atherosclerotic plaque formation.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"background-color: #f0f0f0;padding: 5px;text-align: left\"><sup><strong>Histopathology of atherosclerosis (aorta)<\/strong> by Tetiana Povshedna licensed under CC BY 4.0 created with BioRender.com. Histology slides are DHPLC specimens PATH 425-032 (fat stain) and PATH 425-033 (elastin stain)<\/sup><\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox textbox--key-takeaways\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Fat Tissue Stain: Key Takeaways<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<ul>\n<li>Irregularly thickened <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a> as a result of lipid accumulation<\/li>\n<li>Numerous lipid deposits in both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1034\">tunica media<\/a><\/li>\n<\/ul>\n<p>On a cellular level, this stage of atherosclerosis development is associated with the pro-inflammatory state, macrophage recruitment, and foam cell formation with subsequent necrotic core development.<\/p>\n<\/div>\n<\/div>\n<div class=\"textbox textbox--key-takeaways\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Elastin Stain: Key Takeaways<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<div class=\"textbox__content\">\n<ul>\n<li>Irregularly thickened <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a>; loss of elastic fibers in tunica intima (compare this elastic stain to an example of the normal human aorta in&nbsp; <a href=\"https:\/\/pressbooks.bccampus.ca\/pathology\/chapter\/normal-blood-vessel-anatomy-histology\/\">Gross anatomy and histology of normal aorta<\/a> and note the amount of elastic fibers in tunica intima)<\/li>\n<li>Elastic tissue appears compressed and fragmented in the superficial layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1034\">tunica media<\/a>. This fragmentation and weakening of the aorta wall might facilitate the formation of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1177\">aneurysm&nbsp;<\/a><\/li>\n<li>On higher magnification, cholesterol crystals appear as stellate empty spaces in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a><\/li>\n<li>Areas of calcification appear as dark dense spots within tunica intima<\/li>\n<\/ul>\n<\/div>\n<p>Type your key takeaways here.<\/p>\n<ul>\n<li>First<\/li>\n<li>Second<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<p>&nbsp;<\/p>\n<p>While all the histological slides and gross anatomy specimens above focused on various regions of aorta as a site of atherosclerotic plaque formation, coronary arteries are also one of the common and clinically relevant sites of atherosclerosis. Plaque formation within these arteries can cause <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1152\">hypoxia<\/a> of the heart muscle which, if left untreated, can lead to a heart attack.<\/p>\n<p>The video below examines the key features of atherosclerosis in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_962\">coronary arteries<\/a>. Clinically, these changes would reflect the pathophysiology of ischemic heart disease.<\/p>\n<p>&nbsp;<\/p>\n<p style=\"background-color: #f0f0f0;padding: 5px;text-align: left\"><sup><em><strong>Histopathology of atherosclerosis (coronary artery).<\/strong> Created and presented by Jonathan Bush.&nbsp; Histology slide is from private collection.&nbsp;<\/em><\/sup><\/p>\n<div><\/div>\n<div class=\"textbox shaded\">\n<p>Key takeaways:<\/p>\n<ul>\n<li>numerous immune cells in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1032\">tunica externa <\/a>reflect inflammatory process triggered by atherosclerosis<\/li>\n<li>a blood clot is obstructing the lumen, making tunica intima hard to identify<\/li>\n<li>fibrotic areas (appear pale pink and do not contain a lot of cell nuclei) reflect lipid accumulation<\/li>\n<li>foam cells that engulfed oxidized LDL&nbsp; in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1034\">tunica media&nbsp;<\/a><\/li>\n<\/ul>\n<\/div>\n<h2>Clinical outcomes of severe atherosclerosis (gross anatomy)<\/h2>\n<h3><strong>Thrombosis of atherosclerotic aorta&nbsp;<\/strong><\/h3>\n<p>The formation of a clot is one of the common clinical outcomes of severe atherosclerosis. Thrombosis-induced <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1153\">ischemia <\/a> can result in heart attack or stroke, depending on location. Clot formation as a result of atherosclerosis in coronary vessels can block the blood flow to the heart, and cause tissue damage as a result of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1152\">hypoxia<\/a>. Similar scenarios can occur anywhere along the vascular tree, including the brain (stroke), lower limb (peripheral artery disease), etc.<\/p>\n<p>This specimen demonstrates a case of thrombosis in the abdominal aorta as a result of atherosclerosis.<\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">\n<p><strong>Patient history:&nbsp;<\/strong><\/p>\n<p>An elderly man with a history of peripheral artery disease &#8211; a manifestation of atherosclerosis in lower limbs, which resulted in bilateral leg amputation two years previously. Chief complaint on admission &#8211; pain. Cause of death &#8211; pneumonia; autopsy revealed generalized atherosclerosis.<\/p>\n<p>The specimen demonstrates distal abdominal aorta as it divides into the right and left<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1191\"> common iliac arteries<\/a>.<\/p>\n<p><strong>Key observations: <\/strong><\/p>\n<ul>\n<li><em><strong>narrowing<\/strong><\/em> of the distal aorta by a dark thrombus which extends into common iliac arteries<\/li>\n<li><em><strong>thickening<\/strong> <\/em>of the aorta wall &#8211; numerous yellow atherosclerotic plaques that narrow the lumen<\/li>\n<li>typical<em><strong> location<\/strong> <\/em>of the plaque and thrombus &#8211; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1173\">bifurcation<\/a> of a large vessel where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1171\">laminar<\/a> flow becomes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1172\">turbulent<\/a><\/li>\n<\/ul>\n<\/div>\n<figure id=\"attachment_4911\" aria-describedby=\"caption-attachment-4911\" style=\"width: 1280px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4911 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Thrombosis-of-atherosclerotic-aorta.png\" alt=\"the abdominal aorta is cut open to reveal the inner intimal surface. On the left of the image, the proximal aorta shows yellow-white atherosclerotic plaques. In the middle of the image, the entire luminal space is filled with a dark blood thrombus (clot) centered around a shaggy atherosclerotic plaque with a needle-thin opening for blood. The right image shows the abdominal aorta splitting into the two common iliac arteries.\" width=\"1280\" height=\"720\" \/><figcaption id=\"caption-attachment-4911\" class=\"wp-caption-text\"><strong>Fig 8.31 Thrombosis of atherosclerotic aorta<\/strong>. DHPLC specimen C0414. All rights reserved<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3><strong>Aneurysm of atherosclerotic aorta&nbsp;<\/strong><\/h3>\n<p>Severe atherosclerosis can progress towards <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1177\">aneurysm<\/a>, where the muscular layer of the vessel weakens and creates a bulge that can rupture and lead to internal bleeding.<\/p>\n<p>This case demonstrates atherosclerotic aneurysm of the abdominal aorta.<\/p>\n<div class=\"textbox shaded\">\n<p><strong>Patient history:&nbsp;<\/strong><\/p>\n<p>75 y.o. man with a known abdominal aortic aneurysm, presented with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1181\">epigastric<\/a> pain for several days. Physical examination of abdomen revealed a non-painful mass about 10 cm in diameter. Aneurysm <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1182\">dissection<\/a> was suspected. The autopsy revealed atherosclerosis of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1183\">coronary<\/a> vessels, as well as an atherosclerotic abdominal aneurysm with a thrombus.<\/p>\n<p><strong>Key observations:&nbsp;&nbsp;<\/strong><\/p>\n<ul>\n<li>compare and contrast the diameter of abdominal aorta and aneurysm<\/li>\n<li>note numerous atherosclerotic plaques in the proximal part of the aorta<\/li>\n<li>the lumen of the aneurysm if partially filled with a mural thrombus<\/li>\n<li>typical location of atherosclerosis\/aneurysm &#8211; at the bifurcation of the abdominal aorta into right and left <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1191\">common iliac arteries<\/a><\/li>\n<\/ul>\n<p><strong>Compare and contrast the diameter of the abdominal aorta in the above figure and the one below of&nbsp;DHPLC specimens C0414 and C0309<\/strong><\/p>\n<\/div>\n<figure id=\"attachment_4912\" aria-describedby=\"caption-attachment-4912\" style=\"width: 1280px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4912 size-full\" src=\"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-content\/uploads\/sites\/2131\/2023\/12\/Abdominal-aneurysm.png\" alt=\"The abdominal aorta is opened at the level of the aneurysm, exposing the inside. The aneurysm has many layers, like an onion, with a dark blood clot (thrombus) just off the centre. The bottom of the aorta shows the bifurcation to the common iliac arteries. The top of the image shows the abdominal aorta dotted with yellow white atherosclerotic plaques\" width=\"1280\" height=\"720\" \/><figcaption id=\"caption-attachment-4912\" class=\"wp-caption-text\"><strong>Fig 8.32. Atherosclerotic aneurysm of aorta<\/strong>. DHPLC specimen C0309 All rights reserved.<\/figcaption><\/figure>\n<h1>Section review<\/h1>\n<p>On gross anatomy specimens, early atherosclerotic lesions appear as yellow streaks\/patches on the luminal side of the vessel. As the severity of atherosclerosis increases, atherosclerotic plaques grow in size and number and can cause ulceration. Advanced atherosclerotic vessels have an irregular luminal surface, numerous plaques, areas of calcification, ulceration, and clot formation. One of the most common clinical outcomes of advanced atherosclerosis is an aneurysm or clot formation.<\/p>\n<p>Histologically, lipid deposits are visible within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\"> tunica intima<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1034\">tunica media <\/a> of atherosclerotic vessels. Endothelial damage, which is necessary for lesion initiation, is often present. During the advanced stages, cholesterol crystals and calcium deposits can be visualized in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1033\">tunica intima<\/a>, while <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_372_1034\">tunica media<\/a> can appear fragmented.<\/p>\n<h1>Review questions<\/h1>\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_372_1033\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1033\"><div tabindex=\"-1\"><p>(also, tunica interna) innermost lining or tunic of a vessel<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1184\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1184\"><div tabindex=\"-1\"><p>bleeding<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1179\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1179\"><div tabindex=\"-1\"><p>same as atherosclerotic plaque<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1169\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1169\"><div tabindex=\"-1\"><p>elevated blood pressure<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1034\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1034\"><div tabindex=\"-1\"><p>middle layer or tunic of a vessel (except capillaries)<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1177\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1177\"><div tabindex=\"-1\"><p>abnormal ballooning\/ widening of the blood vessel wall cause by it's weakness. Aneurysm rupture is very dangerous and often fatal<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1152\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1152\"><div tabindex=\"-1\"><p>lack of oxygen supply to the tissues<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_962\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_962\"><div tabindex=\"-1\"><p>branches of the ascending aorta that supply blood to the heart; the left coronary artery feeds the left side of the heart, the left atrium and ventricle, and the interventricular septum; the right coronary artery feeds the right atrium, portions of both ventricles, and the heart conduction system<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1032\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1032\"><div tabindex=\"-1\"><p>(also, tunica adventitia) outermost layer or tunic of a vessel (except capillaries)<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1153\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1153\"><div tabindex=\"-1\"><p>insufficient blood flow to the tissues<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1191\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1191\"><div tabindex=\"-1\"><p>a large artery that carries oxydenated blood to lower limbs, pelvis, and reproductive organs<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1173\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1173\"><div tabindex=\"-1\"><p>part of the blood vessel where it splits in 2 branches<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1171\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1171\"><div tabindex=\"-1\"><p>type of fluid flow in which fluid travels smoothly <\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1172\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1172\"><div tabindex=\"-1\"><p>type of fluid flow in which fluid undergoes irregular fluctuations and mixing<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1181\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1181\"><div tabindex=\"-1\"><p>upper abdomen, below the ribs<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1182\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1182\"><div tabindex=\"-1\"><p>injury to the inner layer of the vessel, separation (tear) of blood vessel wall that allows for blood to flow between the layers; a medical emergency<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_372_1183\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_372_1183\"><div tabindex=\"-1\"><p>arteries that supply heart muscle<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":103,"menu_order":16,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["tetiana-p"],"pb_section_license":""},"chapter-type":[],"contributor":[178],"license":[],"class_list":["post-372","chapter","type-chapter","status-web-only","hentry","contributor-tetiana-p"],"part":306,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapters\/372","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/wp\/v2\/users\/103"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapters\/372\/revisions"}],"predecessor-version":[{"id":1283,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapters\/372\/revisions\/1283"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/parts\/306"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapters\/372\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/wp\/v2\/media?parent=372"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/pressbooks\/v2\/chapter-type?post=372"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/wp\/v2\/contributor?post=372"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/dcbiol2200\/wp-json\/wp\/v2\/license?post=372"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}