dyslpidemia Flashcards
What is cholesterol, and where is it synthesised?
Cholesterol is a steroid that is synthesised by all animal cells, especially the liver. It is also an integral part of cell membranes.
What is a triglyceride, and what is it composed of?
A triglyceride is a form of fat within the blood composed of glycerol and 3 fatty acids, which are esters.
What are lipoproteins, and why are they important in the blood?
Lipoproteins are molecules that carry fats in the blood as they are immiscible with water. They are important because they transport cholesterol, triglycerides, and apolipoproteins throughout the body.
What are the core and surface components of lipoproteins?
The core of lipoproteins contains cholesterol esters and triglycerides, while the surface contains free cholesterol, apolipoproteins, and phospholipids.
What are the different subtypes of lipoproteins?
The different subtypes of lipoproteins include HDL (high-density lipoproteins), LDL (low-density lipoproteins), IDL (intermediate-density lipoproteins), VLDL (very-low-density lipoproteins), and chylomicrons.
What is the function of HDL, LDL, IDL, VLDL, and chylomicrons?
HDL delivers cholesterol from the tissues to the liver and is also known as “good cholesterol,” while LDL delivers cholesterol from the liver to the tissues and is also known as “bad cholesterol.” IDL is an intermediate form between VLDL and LDL, while VLDL delivers triglycerides from the liver to the tissues. Chylomicrons deliver triglycerides and cholesterol from the intestines into the liver.
What is the basic cholesterol pathway in the liver?
In the liver, acetyl CoA is converted to HMG CoA by the action of HMG-CoA reductase. This is then converted to mevalonate, which is the precursor for cholesterol and bile acid synthesis.
What is the exogenous pathway for cholesterol transport?
The exogenous pathway for cholesterol transport involves dietary fats being transported from the gut in chylomicrons, with the triglyceride component broken down by lipoprotein lipase in the endothelium. The remnants are then transported to the liver, which secretes bile acids and some cholesterol into the gut.
What are the endogenous pathways for cholesterol transport?
What are the endogenous pathways for cholesterol transport?
What is the reverse pathway for cholesterol transport?
What is the reverse pathway for cholesterol transport?
What are some causes of dyslipidaemia?
Some causes of dyslipidaemia include diabetes mellitus, hypothyroidism, chronic kidney disease, chronic liver disease, obesity, smoking, medications (e.g., thiazide diuretics), and alcohol excess (which can increase triglyceride levels).
What are the causes of primary dyslipidaemia?
The causes of primary dyslipidaemia include abnormalities in lipoprotein structure or abnormalities in lipoprotein receptors.
What is Type I familial hyperchylomicronaemia, and what lipoproteins are elevated?
Type I familial hyperchylomicronaemia is a condition in which there is low lipoprotein lipase activity, leading to the accumulation of chylomicrons in the blood. Chylomicrons are the elevated lipoproteins in this condition.
What is Type IIa familial hypercholesterolaemia, and what lipoproteins are elevated?
Type IIa familial hypercholesterolaemia is a condition in which there is a low number of LDL receptors, leading to elevated levels of LDL cholesterol in the blood. LDL is the elevated lipoprotein in this condition.
What is Type IIb familial combined hyperlipidaemia, and what lipoproteins are elevated?
Type IIb familial combined hyperlipidaemia is a condition in which there is high APO B 100, leading to elevated levels of both LDL and VLDL in the blood. Both LDL and VLDL are elevated lipoproteins in this condition.
What is Type III familial dysbetalipoproteinaemia, and what lipoproteins are elevated?
: Type III familial dysbetalipoproteinaemia is a condition in which there is an Apo E mutation, leading to elevated levels of both IDL and chylomicrons in the blood. Both IDL and chylomicrons are the elevated lipoproteins in this condition.
What is Type IV familial hypertriglyceridaemia, and what lipoproteins are elevated?
Type IV familial hypertriglyceridaemia is a condition in which VLDL levels are elevated in the blood. Triglycerides are also elevated in this condition.
What is familial hyperlipidaemia type I?
Familial hyperlipidaemia type I, also known as hyperchylomicronaemia, is a very uncommon genetic condition characterized by a deficiency of lipoprotein lipase, leading to very high triglycerides and normal cholesterol levels.
What is the inheritance pattern of familial hyperlipidaemia type I?
Familial hyperlipidaemia type I is inherited in an autosomal recessive pattern.
How is familial hyperlipidaemia type I diagnosed?
Familial hyperlipidaemia type I can be diagnosed through a blood test that shows very high triglyceride levels and normal cholesterol levels. Additionally, the blood may appear creamy when spun due to the presence of chylomicrons.
What is the difference between familial hyperlipidaemia type I and type IIa?
Familial hyperlipidaemia type I is characterized by very high triglycerides and normal cholesterol levels due to a deficiency of lipoprotein lipase. In contrast, familial hyperlipidaemia type IIa is characterized by very high levels of LDL cholesterol and near normal triglyceride levels.
What is familial hypercholesterolaemia type IIa?
Familial hypercholesterolaemia type IIa is an autosomal dominant genetic condition characterized by very high LDL cholesterol levels, even at birth.
What total cholesterol level is indicative of familial hypercholesterolaemia type IIa?
Familial hypercholesterolaemia type IIa should be considered if the total cholesterol level is greater than 7.5 mmol/L.
What specific mutations cause familial hypercholesterolaemia type IIa?
Familial hypercholesterolaemia type IIa is caused by specific mutations that lead to either the absence or very low levels of LDL receptors.
What are the clinical consequences of familial hypercholesterolaemia type IIa?
Familial hypercholesterolaemia type IIa causes severe atherosclerosis and may lead to ischemic heart disease in young adults, especially men.
What is familial combined hyperlipidaemia type IIb?
Familial combined hyperlipidaemia type IIb is an autosomal dominant genetic condition characterized by moderately high levels of both cholesterol and triglycerides, insulin resistance, and obesity.
What lipids are elevated in familial combined hyperlipidaemia type IIb?
All the ‘bad’ lipids are elevated in familial combined hyperlipidaemia type IIb, including LDL, VLDL, and triglycerides.
What is the cause of familial combined hyperlipidaemia type IIb?
Familial combined hyperlipidaemia type IIb is caused by multiple genetic defects, commonly polygenetic, that involve overproduction of apolipoprotein B-100 (apo B-100).
What is the clinical consequence of familial combined hyperlipidaemia type IIb?
Familial combined hyperlipidaemia type IIb accounts for up to 20% of cases of premature ischemic heart disease (IHD).
What is familial hypertriglyceridaemia type IV?
Familial hypertriglyceridaemia type IV is a genetic condition characterized by elevated triglycerides (>5.0 mmol/L) and relatively normal cholesterol, with HDL often low.
What is the risk associated with high triglyceride levels in familial hypertriglyceridaemia type IV?
There is a risk of acute pancreatitis if the triglyceride level exceeds 10 mmol/L, possibly due to pancreatic capillary obstruction.
Is familial hypertriglyceridaemia type IV strongly associated with ischemic heart disease (IHD)?
No, familial hypertriglyceridaemia type IV is not strongly associated with ischemic heart disease (IHD), although there may be multiple genetic defects involved.
