Lecture subject: ATHEROSCLEROSIS, ESSENTIAL HYPERTENSION.
Atherosclerosis is a chronic disease, appearing as a result of lipid and protein metabolism derangement, characterized by arterial involvement of elastic and musculoelastic type in the form of focal deposition of lipids and proteins in the arteries intima and reactive growth of connective tissue.
Atherosclerosis etiology: 1. Metabolic factors (exo- and endogenic) 2. Hormonal factors 3. Hemodynamic factors 4. Neural factor 5. Vascular factor 6. Hereditary and ethnic factors
Risk factors: 1. 2. 3. 4. 5. 6. Hyperlipidemia Hypodynamia Arterial hypertension Diabetes mellitus Hypothyroidism Heredity
Atherogenic and anti-atherogenic substances o Low-density (LDLP) and very low density lipoproteins (VLDLP) – are atherogenic (cholesterol) o High-density (HDLP) and very high density lipoproteins (VHDLP) – are anti-atherogenic (phospholipids) o They are in the ratio 4: 1 in the normal condition
Pathogenesis of atherosclerosis Etiologic factors lead to atherogenic lipoproteidemia and increase of artery wall membranes permeability → injury of arteries endothelium → accumulation of VLDLP and LDLP in the arteries intima → proliferation of unstriped muscle cells and macrophages and their transformation into foam cells.
Morphology and morphogenesis: Macroscopic and microscopic stages of atherosclerosis have to be distinguished.
Stages of atherosclerosis (macroscopic): 1. Fat stains and stripes (stains and stripes of yellow color, not raised above the intima surface) 2. Fibrous plaques (solid, whitish formations, raised above the intima surface – atherosclerotic plaques) 3. Complicated affections/lesions (atheromatosis, hemorrhages in the plaque, formation of thrombi) 4. Atherocalcinosis (solid, white as a stone)
Stages of atherosclerosis (microscopic): 1. Prelipidic stage 2. Lipoidosis (corresponds to fat stains and stripes) 3. Liposclerosis (corresponds to fibrous plaques) 4. Atheromatosis (corresponds to the 3 rd stage macro) 5. Atherocalcinosis (corresponds to the 4 th stage macro)
Stages of atherosclerosis (microscopic): 1. Prelipidic stage (macro: no changes, increase of endothelium permeability) 2. Lipoidosis (lipids infiltrate the intima) 3. Liposclerosis (in the plaque center – lipids and proteins, on the periphery– connective tissue and newly formed vessels) 4. Atheromatosis (lipoprotein detritus, fibers destruction, arrosion of plaque vessels tissue) 5. Atherocalcinosis (lime in the form of granules and plates of violet color when stained with hematoxylin/eosin)
Atherosclerotic plaque (scheme) 1 – cover, 2 – lipids in the plaque center, 3 – sclerosis, 4 – petrification, 5 – foci of metachromasia, 6 – fibrin, 7 – unstriped muscle cells.
Clinicopathologic forms of atherosclerosis: 1. 2. 3. 4. 5. 6. Atherosclerosis Atherosclerosis extremities of of of aorta coronary arteries cerebral arteries renal arteries intestinal arteries of low
In case of atherosclerosis of any localization the manifestations can be dual: o If the atherosclerotic plaque does not block the artery lumen fully – chronic ischemia is appearing → dystrophy, atrophy of parenchyma and stroma sclerosis o If the plaque is blocking the artery lumen fully – acute ischemia and necrosis (infarction) appear in the tissue
Atherosclerosis of aorta
Atherosclerosis of arteries of heart and cerebral arteries underlies the coronary heart disease (CHD) and cerebrovascular disease (CVD) correspondingly.
Atherosclerosis of renal arteries leads to the development of atherosclerotic macrotuberous kidney
Atherosclerotic nephrosclerosis
Atherosclerosis of arteries of low extremities leads to intermittent claudication (partial blocking of artery by the plaque) or to gangrene (fully blocking of femoral artery by the plaque or thrombus)
Atherosclerosis of mesenteric arteries leads to the bowels gangrene
Essential hypertension
Essential hypertension is a chronic disease, characterized by the stable rise of arterial pressure of neurogenic nature, not connected with the primary injury of any organ AP= 120 and 80 mm of mercury
Risk factors: o Stress, psychoemotional overstrain o Heredity o Increased use of sodium chloride (table salt)
Hypertension course: o malignant o benign
Malignant hypertension: Diastolic pressure – 120 mm of mercury More often in young men (30 -35 years old) Renal form is dominant In kidneys – fibrinoid necrosis of arterioles and capillary loops of glomeruli. Renal insufficiency is appearing fast o No stages observed o Death cause – renal insufficiency, cerebral hemorrhages o o
Benign course of hypertension
3 stages: 1. Pre-clinical 2. Generalized changes of small arteries and arterioles 3. Secondary changes in organs connected with the changes of arteries and derangement of intraorganic blood flow
Pre-clinical stage: 1. Transient hypertension 2. Hypertrophy of muscle layer of arterioles 3. Moderate compensatory hypertrophy of myocardium (left ventricle wall thickness > 1, 2 сm)
Stage of the generalized changes of arteries: 1. Stable rise of arterial pressure 2. In the small arteries – plasma transudation, hyalinosis 3. Elastosis, elastofibrosis – hyperplasia and splitting of internal elastic membrane, followed by sclerosis (fibrosis) 4. Myocardial hypertrophy is increasing ! In case of hypertension combination with atherosclerosis the fibrous plaques are forming even in small arteries!
Elastosis of vessels
Stage of organ changes 1. Dystrophy of parenchyma 2. Atrophy of parenchyma and stroma sclerosis 3. Arteries occlusion (spasm, thrombosis, fibrinoid necrosis, infarctions, hemorrhages) 4. Cerebral hemorrhages are dangerous 5. In kidneys – arteriolosclerotic nephrosclerosis – “primary wrinkled kidneys”
“Primary wrinkled kidneys”
Types of cerebral hemorrhages: o Without the structure destruction – diapedetic o With the structure destruction – hematomas o Especially dangerous – hemorrhages in basal ganglia of brain, brainstem, break into ventricles of brain
Clinicomorphologic forms of hypertension: o Cardiac (CHD) o Cerebral (CVD) o Renal (arteriolonecrosis, infarction, arteriolonecrotic nephrosclerosis)
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