LIPIDS lec

Lipids

- "fats" it helps in moving and storing energy, absorbing vitamins and making hormones.

- It is insoluble to blood but soluble to organic solvents.

carbons-hydrogens (C-H)

Lipids is composed of mostly ______________________

Vitamin A, D, E, K

Lipids are important in the utilization of fat soluble vitamins namely?

Organic solvents

Volatile alcohols, carbon-based substances capable of dissolving or dispersing one or more other

substances.

Can be: carcinogens, neurotoxins, reproductive hazards.

Cholesterol, triglycerides, HDL, LDL, VLDL

Lipid profile is composed of?

Classification of Lipids

1. Fatty acids

2. Triglycerides

3. Cholesterol

4. Phospholipids

VLDL, LDL, HDL

lipids are transported by?

Fatty acids

CLASSIFICATION OF LIPIDS:

- It is the building blocks of the fat in our bodies.

- Linear chains of C-H bonds that terminated with -COOH

- they provide the substance for conversion to glucose

hydrolysis of triglycerides

Fatty acids are derived from the _________ in adipose tissues

Free unesterified form

What is the form of the small amount of fatty acids present in plasma and is most bound to albumin?

Esterified

- a constituent of triglycerides or phospholipids

Bonds of fatty acids

- saturated

- monosaturated

- polyunsaturated

Saturated

No double bonds

Monosaturated

Single bonds

Polyunsaturated

≥ Double bonds

Polyunsaturated and cis-monounsaturated

Fatty acids that are not associated with elevated serum LDL cholesterol

• healthy (found in animal products)

Ester

any of class of organic compounds that react with water to produce alcohols and organic/inorganic acids

carboxylic acid

esters are derived from?

Classification of ester

1. As to chain

2. As to the number of C=C bonds

Ester chain

- short (4-6 carbon atoms)

- medium-chain (8-12 carbon atoms)

- long chain (>12 carbon atoms)

Ester C=C bonds

- Saturated (without double bonds) fatty acids

- Unsaturated (with double bonds) fatty acids.

9-15mg/dl

Reference range of fatty acids

Gas chromatography or HPLC

fatty acids are measured by

Albumin

Majority of fatty acids are bound to ____________

Triglyceride

Classification of Lipids:

Triacyglycerol (neutral fat)

- provides excellent insulation

- the main storage of lipid in man

- does not contain charged or hydrophilic groups

- VERY HYDROPHOBIC and WATER INSOLUBLE

3 molecules of fatty acids, 1 molecule of glycerol

Triglycerides contain __________which is attatched to_________

Saturated and unsaturated

Triglycerides contain what type of fatty acids?

Saturated fatty acids

Unhealthy fats

- transfat

- solid at room temp

Unsaturated fatty acids

These fats are liquid at room temp

95% stored fat, glyceryl ester

TAG constitutes of __________ and the predominant form of ________ found in plasma

LPL, epinephrine, cortisol

TAG Breakdown is facilitated by?

Lipoprotein lipase (LPL)

- enzyme that breaks down glyceride

- only helps but does not facilitate

Epinephrine

Increases lipolysis when there is a need for a burst of energy

Cortisol

Increases lipolysis by releasing stress hormones which releases energy

10-12hrs, 11hrs as standard

TAG fasting requirement

<150 mg/dL

Reference value for TAG: normal

150-199 mg/dL

Reference value for TAG: borderline high

200-499 mg/dL

Reference value for TAG: high TAG

>500 mg/dL

Reference value for TAG: very high TAG (acute & recurrent pancreatitis)

Coronary artery disease

Diagnostic significance:

Fasting TAG ≥ 200 mg/dl are at risk for ____________ because of atherogenic VLDL remnants.

Atherosclerosis

Diagnostic significance:

It evaluates suspected _______ and measures the body's ability to metabolize fat

Phospholipids

Classification of Lipids:

- "conjugated lipids" most abundant lipids

- amphipathic lipid

- similar to TAG but they contain 2 fatty acids

lipid bound phosphate

the presence of ____________ is the only unique structural feature of phospholipid which is a feature common to all phospholipids

Amphipathic lipid

contains:

- polar hydrophilic head groups

- non-polar hydrophobic fatty acid side chains

Lamellar bodies

In the lungs, phospholipids is produced by type II pneumocytes in the form of?

Phospatidic Acid

phospholipids are derived from __________________

- for cellular signaling and membrane dynamics

Glycerol and Phosphate group

Phospholipids contain two fatty acids attached to one molecule of ______________ and a ________________ group

150-380 mg/dl

Reference range of phospholipids: (serum)

Functions of phospholipids

- alter fluid surface tension (the decrease surfae tension w/in alveolar space for expiration

- decrease in surfactant = neonatal respiratory distress syndrome

- participate in cellular metabolism and blood coagulation

- important substrates for lipoprotein metabolizing enzymes

Forms of phospholipids

1. Lecithin/Phosphatidylcholine

2. Sphingomyelin

3. Cephalin

Lecithin/Phosphatidylcholine (70%)

Forms of phospholipids:

Ratio for FLM (≥2)

Sphingomyelin (20%)

Forms of phospholipids:

- essential component of cell membranes (RBC and nerve sheath)

- reference material FLM during 3rd trimester of pregnancy

sphingosine

sphingomyelin is derived from this.

- amino alcohol that can acummulate causing neimann's pick disease

Niemann's Pick disease

Lipid storage disorder

- abnormal amounts of lipids (fatty materials such as waxes, oils, and cholesterol)

- build up in the brain, spleen, liver, lungs, and bone marrow.

Cephalin (30%)

Forms of phospholipids:

Consists of

- Phosphatidyl ethanolamine

- Phosphatidyl serine

Lysolecithin +Inositol Phosphatide

Cholesterol "3-hydroxy-5-6-cholestene"

Classificatio of Lipids:

- Waxy substance found in your blood.

- Unsaturated steroid alcohol contain four rings and single C-H side chain

- Amphipathic

Estrogen, lipid layers

The transport and excretion of cholesterol is promoted by?

it is also found in the surface of?

animals, doesnt serve as fuel

cholestreol is almost exclusively synthesized by?

- also not catabolized = _________

20yrs +, once every 5 years

Cholesterol should be measured in all adults ages...

<200mg/dl

Reference values of cholesterol:

Desirable

200-239 mg/dl

Reference values of cholesterol:

Borderline

≥ 240 mg/dl

Reference values of cholesterol:

High cholesterol (cholelithiasis/gall stone)

Cholelithiasis/gall stone

disease of high cholesterol

- fatty live = high cholesterol and SGPT

- bile stones = emulsification of fats

functions of cholesterol

- precursor of major classes of steroids

- constituesnt in assemply of cell membraned and bile acids

Major classes of steroids

- Progestins Glucocorticoids

- Mineralocorticoids

- Androgens

- Estrogens

- Progestins Glucocorticoids

- Mineralocorticoids

- Androgens

- Estrogens

Major classes of steroids

Vitamin D3

small amount of cholesterol --> 7-dehydrocholesterol --> ?

- transformed by sunlight irradiation

Atherosclerosis, Myocardial and Coronary arterial occlusions

Diagnostic significance of cholesterol:

it evaluates the risk for?

A

M

C

serum cholesterol, myocardial infarction

Diagnostic significance of cholesterol:

There is a direct relationship between elevated ?(SC) and ?(MI)

lipoprotein disorders

Diagnostic significance of cholesterol:

it is essential in the diagnosis and management of?

Forms of Cholesterol

1. Cholesterol Ester (CE)

2. Free Cholesterol (FC)

Cholesterol Ester (CE) (70%)

"neutral lipid" (not charged)

- Found in plasma and serum

- bound to Fatty acid (hydrophobic form)

- located in center of lipid drops with lipoprotein and TAG

Lecithin cholesterol acyltransferase

catalyzes the esterification of cholesterol

- synthesized in the liver

cholesterol ester

LCAT accumulates blood cholesterol (HDL) as?

Apo A-1

Activator of LCAT

- most abundant protein in HDL.

- modulates interactions that affect HDL's cardioprotective functions

Free cholesterol (FC) (30%)

- found in plasma, serum, RBCs, and surface of lipoproteins

- polar non-esterified alcohol

Lipoprotein

It is composed of both lipids and protein (apolipoprotein)

functions of lipoprotein

• Maintain structural integrity

• Ligands for cell receptor

• Activators and inhibitors of enzymes

• Amphipathic

• Maintain structural integrity

• Ligands for cell receptor

• Activators and inhibitors of enzymes

• Amphipathic

functions of lipoprotein

absorption and transport of dietary lipids

lipoproteins plays a key role in the ____________and the _____________of _________________ by the small intestine

- transport of lipids from the liver to peripheral tissues.

- transport of lipids from peripheral tissues to the liver and intestine (reverse cholesterol transport)

LIPOPROTEIN METABOLISM (lipolytic enzymes)

1. LPL - Lipoprotein lipase

2. Hepatic Lipase

3. Lecithin Cholesterol Acyl Transferase

4. Endothelial lipase

Lipoprotein Structure (Major Types)

1. Chylomicrons

2. VLDL - very low density lipoprotein

3. LDL - low density lipoprotein

4. HDL - high density lipoprotein

Chylomicrons

- Largest and least dense,

- produced in the intestine

- for the delivery of dietary lipids to hepatic and peripheral cells

- cleared 6-9 hours post prandial

<0.93 g/ml

Density of chylomicrons

VLDL - very low density lipoprotein

"pre-beta lipoprotein"

- Produced in the Liver

- Transfer triglycerides from the liver to peripheral tissue

0.93 - 1.006 g/ml

density of VLDL

LDL - low density lipoprotein

"Beta lipoprotein" or "bad cholesterol"

- Formed from lypolysis of VLDL to IDL then to LDL

- Transfer dietary cholesterol to peripheral tissues

1.019 - 1.063 g/mL

Density of LDL

Assesment factor for Coronary heart disease

LDL CHD:

<130 mg/dl - desirable

130-159 mg/dl - borderline

>160 mg/dl - high risk

HDL - high density lipoprotein

"Alpha lipoprotein" or "good cholesterol"

- Produced in the Liver and the Intestine

- Transfer cholesterol from peripheral cells back to the liver

- Smallest LP

1.063-1.210 g/mL

Density for HDL

Lipoprotein Structure (Minor Types)

1. Lipoprotein (a)

2. Lipoprotein X

3. IDL- intermediate-density lipoprotein

4. beta-VLDL

Lipoprotein (a)

LDL lipoprotein-like particle

- Confers increased risk for premature coronary heart disease and stroke. - Competes with plasminogen for fibrin

Lipoprotein X

- Abnormal CHON

found in:

- obstructive jaundice

- LCAT deficiency

- Indicator of cholestasis

IDL- intermediate-density lipoprotein

subclass of LDL

- migrates between Beta and pre-beta region

beta-VLDL

Floating Lipoprotein

found in:

- hyperlipoproteinemia type 3 (dysbetalipoproteinemia)

Lipoprotein Metabolism

1. Lipid Absorption

2. Exogenous Pathway

3. Endogenous Pathway

4. Reverse Cholesterol Pathway

Arteriosclerosis

LIPID DISORDERS:

It is an vascular disease

- blood vessels carrying oxygen away from the heart (arteries) become damaged from:

a. high cholesterol

b. high blood pressure

c. diabetes

d. certain genetic influences.

Hyperlipoproteinemia

LIPID DISORDERS:

The inability to break down lipids or fats in your body

- Specifically:

Cholesterol and Triglycerides:

a. Hypercholesterolenemia

b. Hypertriglyceridemia

c. Combined hyperlipidemia

Hypolipoproteinemia

LIPID DISORDERS:

The unusually low levels of fats (lipids) in the blood.