4. MMeettaabboolliicc RRaattee -- tthe amount of energy liberated per unit of time.
The amount of energy liberated by the catabolism of food in the body is the
same as the amount liberated when food is burned outside the body.
The energy liberated by catabolic processes in the body is used for
maintaining body functions, digesting and metabolizing food,
thermoregulation, and physical activity. It appears as external work, heat,
and energy storage:
= + +
EENNEERRGGYY
OOUUTTPPUUTT
EEXXTTEERRNNAALL
WWOORRKK
EENNEERRGGYY
SSTTOORRAAGGEE
Isotonic muscle contractions perform work at a peak efficiency
approximating 50%:
= /
HHEEAATT
WWOORRKK DDOONNEE TTOOTTAALL EENNEERRGGYY
EEXXPPEENNDDEEDD
EEFFFFIICCIIEENNCCYY
CCaalloorriieess
TThhee ssttaannddaarrdd uunniitt ooff hheeaatt eenneerrggyy iiss tthhee ccaalloorriiee ((ccaall)),, ddeeffiinneedd aass tthhee aammoouunntt
ooff hheeaatt eenneerrggyy nneecceessssaarryy ttoo rraaiissee tthhee tteemmppeerraattuurree ooff 11 gg ooff wwaatteerr 11 ddeeggrreeee,,
ffrroomm 1155 °°CC ttoo 1166 °°CC.. TThhiiss uunniitt iiss aallssoo ccaalllleedd tthhee ggrraamm ccaalloorriiee,, ssmmaallll ccaalloorriiee,,
oorr ssttaannddaarrdd ccaalloorriiee.. TThhee uunniitt ccoommmmoonnllyy uusseedd iinn pphhyyssiioollooggyy aanndd mmeeddiicciinnee iiss
tthhee CCaalloorriiee ((kkiillooccaalloorriiee;; kkccaall)),, wwhhiicchh eeqquuaallss 11000000 ccaall..
9. Transports diet-derived triglyceride (TG) in the blood
Composition:
(1) Protein (2%); (2) TG (87%); (3) Cholesterol (CH;3%); (4) Phospholipid (8%)
Synthesized in intestinal epithelium
(1) Requires apolipoprotein (apo) B-48 for assembly and secretion
(2) Nascent chylomicrons in the circulation obtain apo C-Il and apo E from high
density lipoprotein (HDL)
Absent during fasting
If increased, it forms a creamy supranate.
• 1) Test tube must be left upright in a refrigerator overnight,
• 2) Chylomicron floats on top of plasma because it has very little protein (low
density).
Source of fatty acids and glycerol
• Used to synthesize TG in the liver and adipose
Hydrolysis by capillary lipoprotein lipase (CPL) leaves a chylomicron remnant,
• Chylomicron remnants arc removed by apo E receptors in the liver.
10. Lipoprotein Functions Apoproteins Functions
Chylomicrons
Transport dietary triglyceride and
cholesterol from intestine to
tissues
apoB-48
apoC-II
apoE
Secreted by intestine
Activates lipoprotein lipase
Uptake of remnants by the
liver
VLDL
Transports triglyceride from liver
to tissues
apoB-100
apoC-II
apoE
Secreted by liver
Activates lipoprotein lipase
Uptake of remnants (IDL) by
liver
IDL
(VLDL
remnants)
Picks up cholesterol from HDL to
become LDL
Picked up by liver
apoE
apoB-100
Uptake by liver
LDL
Delivers cholesterol into cells ApoB-100 Uptake by liver and other
tissues via LDL receptor
(apoB-100 receptor)
HDL
Picks up cholesterol accumulating
in blood vessels
Delivers cholesterol to liver and
steroidogenic tissues via
scavenger receptor (SR-B1)
Shuttles apoC-II and apoE in
blood
apoA-1 Activates lecithin cholesterol
acyltransferase (LCAT) to
produce cholesterol esters
11. Transports liver-synthesized TG in the blood
- Requires apolipoprotein B-100 for assembly and secretion
Composition:
• (1) Protein (9%); (2) TG (55%); (3) CH (17%); (4) Phospholipid (19%).
Source of fatty acids and glycerol
• 1) Used to synthesize TG in the adipose tissue
• 2) Hydrolysis by CPL produces intermediate-density lipoprotein (IDL) and low density
lipoprotein (LDL).
• 3) Some of the IDL is removed from blood by apo E receptors in the liver.
Cholesterol ester transport protein (CETP)
(1) Transfers CH from HDL to VLDL;
(2) Transfers TG from VLDL to HDL;
(3) An increase in VLDL always causes a decrease in HDL-CH.
If increased, it forms a creamy infranate.
• Note that the protein is greater in VLDL than in chylomicrons, so it sinks rather than floats in
plasma.
TG levels
• (1) Optimal level < 150 mg/dL
• (2) Borderline high level 150 to 199 mg/dL
• (3) High level 200 to 499 mg/dL,
• (4) Very high level > 500 mg/dL
13. “Good cholesterol”
• Increased by exercise, wine, estrogen
Composition: 1) Protein (50%); 2) TG (3%; unless VLDL is increased); 3) CH (20%);
4) Phospholipid (27%)
Synthesized by the liver and small intestine
Functions of HDL
1) Source of apolipoproteins for other lipoprotein fractions
2) Removes cholesterol from atherosclerotic plaques
a) Delivers CH from peripheral tissue to the liver
b) CH is either excreted into bile or converted into bile acids/salts.
Measured in the laboratory as HDL-CH
1) Inverse association of levels of HDL-CH and incidence and prevalence of CHD
2) Decreased if VLDL is increased
3) Ranges of HDL-CH
(a) High level (optimal) ≥ 60 g/dL
(b) Low level (suboptimal) < 40 mg/dL
4) Fasting is not required for an accurate serum HDL-CH.
Same reason as for serum CH.
17. In many tissues, aacceettyyll--CCooAA uunniittss condense to ffoorrmm aacceettooaacceettyyll--CCooAA.
In the lliivveerr, which (unlike other tissues) ccoonnttaaiinnss aa ddeeaaccyyllaassee, free aceto-acetate is formed.
This ββ--kkeettoo aacciidd is converted to ββ--hhyyddrrooxxyybbuuttyyrraattee and aacceettoonnee, and because these
compounds are metabolized with difficulty in the liver, they diffuse into the circulation.
AAcceettooaacceettaattee is also formed in the liver via the formation of 3-hydroxy-3-methylglutaryl-CoA,
and this pathway is quantitatively more important than deacylation.
AAcceettooaacceettaattee, ββ--hhyyddrrooxxyybbuuttyyrraattee, and aacceettoonnee are called kkeettoonnee bbooddiieess ((KKBB)).
Tissues other than liver transfer CoA from succinyl-CoA to acetoacetate and metabolize the
"active" acetoacetate to CO2 and H2O via the citric acid cycle. There are also other pathways
whereby ketone bodies are metabolized.
AAcceettoonnee is discharged in the urine and expired air.
The normal blood ketone level in humans is low (about 1 mg/dL) and less than 1 mg is
excreted per 24 hours, because the ketones are normally metabolized as rapidly as they are
formed. However, if the eennttrryy ooff aacceettyyll--CCooAA iinnttoo tthhee cciittrriicc aacciidd ccyyccllee iiss ddeepprreesssseedd because of a
ddeeccrreeaasseedd ssuuppppllyy ooff tthhee pprroodduuccttss ooff gglluuccoossee mmeettaabboolliissmm, or if the entry does not increase
when the supply of acetyl-CoA increases, acetyl-CoA accumulates, the rate of condensation to
acetoacetyl-CoA increases, and mmoorree aacceettooaacceettaattee iiss ffoorrmmeedd iinn tthhee lliivveerr.
The ability of the tissues to ooxxiiddiizzee tthhee kkeettoonneess is soon exceeded, and they accumulate in the
bloodstream (ketosis).
KKBB iinn uurriinnee AAcceettoonnee bbrreeaatthh
KKEETTOONNUURRIIAA
KKBB iinn tthhee bblloooodd
KKEETTOONNEEMMIIAA
ppHH --
AAcciiddoossiiss
DDeehhyyddrraa--
ttaattiioonn
AArree
oossmmoottiicc!!
24. •Role of blood monocytes. Though blood monocytes do
not possess receptors for normal LDL, LDL does appear in
the monocyte cytoplasm to form foam cell. Plasma LDL on
entry into the intima undergoes oxidation. The ‘oxidised
LDL’ formed in the intima performs the following all-important
functions on monocytes and endothelium:
•For monocytes: Oxidised LDL acts to attract, proliferate,
immobilise and activate them as well as is readily taken up
by scavenger receptor on the monocyte to transform it to a
lipid-laden foam cell.
•For endothelium: Oxidised LDL is cytotoxic.
•Death of foam cell by apoptosis releases lipid to form lipid
core of plaque.
27. Endothelial Dysfunction in Atherosclerosis
Ross R. N Engl J Med 1999; 340:115–126.
Macrophages play main
role:
1. They have “scavenger”-
receptors so cholesterol
comes in macrophage
only due to concentration
difference.
2. They can accumulate a
lot of Chl inside (this
process is controlled by
HDLP only)
3. Changed LDLP
stimulate macrophages
activity
30. Formation of an Advanced,
Complicated Lesion in
Atherosclerosis
Ross R. N Engl J Med 1999; 340:115–126.
31. Cholesterol and
lisosomal enzymes
irritates intimae
(because they are the
alien bodies)
Excreation of
proliferation factors
by macrophages,
еndotheliocytes,
lymphocytes,
thrombocytes
SMC migration in intimae
and active
proliferation
collagen and elastin
(capsule for
Cholesterol and
injured vessel wall
isolation)
32. 44 ssttaaggee --
CCOOMMPPLLIICCAATTIIOONNSS
1. THROMBOSIS
(due to endothelium
damage)
2. Ulceration
(necrosis of and
releasing of
lisosomal enzymes
causes damage of
plaque wall)
3. Calcinations
(deposit of insoluble
calcium salts)
33. LDL Particles Promote Atherogenesis
Particle Uptake by
Macrophage
Cholesterol Deposition;
Increased Plaque Burden
Particle Movement into Intima
– – Gradient driven
“The rate of passive diffusion is
increased when the circulating
levels of LDL are elevated.” 1
Enhanced
Endothelial
Dysfunction
Adhesion
molecules MCP-1
Colony-stimulating
factors
PPaarrttiiccllee OOxxiiddaattiioonn
Tissue
PAI-1 factor
Endothelial cceellllss
MMoonnooccyyttee
Particle Retention
– – Lipoprotein particle
binding to proteoglycans
Mildly modified LDL
Extensively modified LDL
1
1 Weissberg PL, Rudd JH. Textbook of Cardiovascular Medicine. 2002. p. 6.
Lumen
Intima
34. CClliinniiccaall EEffffeeccttss
Major sites of atherosclerosis (serially
numbered) in descending order of frequency.
The clinical effects of atherosclerosis depend
upon the size and type of arteries affected. In
general, the clinical effects result from the
following:
1. Slow luminal narrowing causing ischaemia
and atrophy.
2. Sudden luminal occlusion causing
infarction necrosis.
3. Propagation of plaque by formation of
thrombi and emboli.
4. Formation of aneurysmal dilatation and
eventual rupture.
Accordingly, the symptomatic atherosclerotic
disease involves most often the heart, brain,
kidneys, small intestine and lower extremities
The effects pertaining to these organs are:
1) AAoorrttaa—Aneurysm formation, thrombosis and
embolisation to other organs.
2) HHeeaarrtt—Myocardial infarction, ischaemic heart
disease.
3) Brain—Chronic ischaemic brain damage,
cerebral infarction.
4) SSmmaallll iinntteessttiinnee—Ischaemic bowel disease,
infarction.
5) LLoowweerr eexxttrreemmiittiieess—Intermittent claudication,
gangrene.
37. NNaammee LLaabboorraattoorryy FFiinnddiinnggss CClliinniiccaall FFeeaattuurreess TThheerraappyy
Type I: exogenous
hyperlipidemia;
fat-induced
hypertriglyceridemia
Cholesterol normal
Triglycerides increased
three times
Chylomicrons increased
Abdominal pain
Hepatosplenomegaly
Skin and retinal lipid
deposits
Usual onset: childhood
Low-fat diet
Type IIa:
hypercholesterolemia
Triglycerides normal
LDL increased
Cholesterol increased
Premature vascular
disease
Xanthomas of tendons
and bony prominences
Common
Onset: all ages
Low-saturated-fat and low-cholesterol
diet
Cholestyramine (a); Colestipol (b);
Lovastatin (c); Nicotinic acid (d) ;
Neomycin (e).
Intestinal bypass
Type IIb: combined
hyperlipidemia;
carbohydrate-induced
hypertriglyceridemia
LDL, VLDL increased
Cholesterol increased
Triglycerides increased
Same as IIa
Same as IIa; plus carbohydrate
restriction
Clofibrate (f); Gemfibrozil (g)
Lovastatin
a) Cholestyramine (Questran), anion exchange resin; binds bile acids; enhances cholesterol excretion.
b) Colestipol (Colestid), same as cholestyramine.
c) Lovastatin, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor; decreases cholesterol synthesis in
the liver.
d) Nicotinic acid (niacin), decreases release of free fatty acids from adipose tissue; increases lipogenesis in liver;
decreases glucagon release; most effective for type V disorder.
e) Neomycin, experimental medication; questionable mode of action; decreases LDLs.
f) Clofibrate (Atromid-S), decreases release of free fatty acids from adipose tissue; decreases hepatic secretion of VLDL
and increases catabolism of VLDL.
g) Gemfibrozil (Lopid), similar to clofibrate but increases HDLs more.
39. a. Epidemiology
1) Autosomal recessive
2) Rare childhood disease
b. Pathogenesis
1) Deficiency of CPL or
2) Deficiency of apo C-ll
c. Clinical findings
1) Chylomicrons are primarily increased in
early childhood.
2) VLDL increases later in life.
3) Presents with acute pancreatitis
• Pancreatic vessels filled with
chylomicrons rupture.
d. Laboratory findings
1) Increase in serum TG 1000 mg/dL
(primarily chylomicrons)
2) Turbid supranate (chylomicrons) and
clear infranate (early childhood)
3) Normal (usual case) to moderately
increased serum CH
A: Lateral borders of thickened
Achilles' tendons are shown with
arrows.
B: Tendinous xanthomas can also
occur in the extensor tendons of
the hands (shown), feet, elbows
and knees.
C: Xanthelasmas are cholesterol
deposits in the eyelids.
D: Arcus cornealis results from
cholesterol infiltration around the
corneal rim (arrow).
40. a. Laboratory findings
1) Serum LDL 190 mg/dL
2) Serum CH 260 mg/dL
a) Serum TG 300 mg/dL (called type IIa)
b) Serum TG 300 mg/dL (called type lIb)
b. Pathogenesis
• Decreased synthesis of LDL receptors.
c. Acquired causes of hypercholesterolemia
1) Primary hypothyroidism
• Decrease in LDL receptor synthesis or
function
2) Nephrotic syndrome
• Increase in LDL correlates with the degree of
hypoalbuminemia
3) Extrahepatic cholestasis (obstruction of bile)
• Bile contains CH for excretion
d. Familial hypercholesterolemia
1) Autosomal dominant (AD) disorder
2) Deficiency of LDL receptors
3) Clinical findings
a) Premature coronary- artery- disease and
stroke
b) Tendon xanthomas
• Cholesterol deposit located over tendons
(e.g. Achilles) and extensor surfaces of
joints
c) Xanthelasma
• Yellow, raised plaque on the eyelid
e. Polygenic hypercholesterolemia (type Ila)
1) Most common hereditary cause (85% of
cases)
2) Multifactorial (polygenic) inheritance
3) Alteration in regulation of LDL levels
4) Normal serum TG
f. Familial combined hypercholesterolemia
(type lIb)
1) AD inheritance.
2) Serum CH and TG begin to increase around
puberty.
3) Associated with metabolic syndrome.
4) Increase in CH and TG and decrease in
HDL.
41. Familial dysbetalipoproteinemia (remnant disease)
1) AD inheritance
2) Deficiency of apo E
3) Decreased liver uptake of chylomicron remnants and IDL
Clinical findings
1) Palmar xanthomas in flexor creases
2) Increased risk for coronary artery disease
3) Increased risk for peripheral vascular
disease (unlike type II disorders)
Laboratorv findings
1) Serum CH and TG 300 mg/dL
2) Serum CH 250 to 500 mg/dL
3) LDL 190 mg/dL
4) Confirm diagnosis with ultracentrifugation to identify remnants
• Lipoprotein electrophoresis and identification of apo E gene defect
are other studies that can be used.
Treatment
• Fibric acid derivatives
42. Laboratory findings
1) Serum TG 300 mg/dL; 2) Serum CH 250 to 500 mg/dL; 3) Serum LDL 190 mg/dL;
4) Turbid infranate after refrigeration
Increase in VLDL - due to increase in synthesis or decrease in catabolism
Acquired causes of hypertriglyceridemia
1) Excess alcohol intake
2) Oral contraceptives - estrogen increases synthesis of VLDL
3) Diabetes mellitus - decreased muscle and adipose CLP
4) Chronic renal failure - increased synthesis of VLDL
5) Thiazides, β-blockers - possible inhibition of CPL
Familial hypertriglyceridemia
1) Autosomal dominant disorder
2) Clinical findings
a) Eruptive xanthomas - yellow, papular lesions
(b) Increased risk for coronary artery- and peripheral
vascular disease
Tubero-eruptive xanthoma
43. a. Pathogenesis
1) Increase in chylomicrons and VLDL
2) Due to decreased activation and release of CPL
b. Familial hypercholesterolemia (type IV) + exacerbating disorder
• Exacerbating disorders — diabetic ketoacidosis (DKA: most common),
alcohol
c. Increased serum TG 1000 mg/dL; normal CH and LDL.
d. Turbid plasma
1) Supranate after refrigeration, due to increased chylomicrons
2) Infranate after refrigeration, due to increased VLDL.
e. Hyperchylomicronemia syndrome
1) Eruptive xanthomas
2) Increased incidence of acute pancreatitis
3) Lipemia retinalis - retinal vessels look like milk: blurry vision
4) Dyspnea and hypoxemia - impaired gas exchange in pulmonary
capillaries
5) Hepatosplenomegaly
6) Increase in serum TG (usually 1000 mg/dL)
7) Normal serum CH and LDL
8) Turbid supranate and infranate after refrigeration
f. Treatment
(1) Treat exacerbating disorder (e.g.. DKA)
(2) Nicotinic acid or fibric acid derivatives
44. Apolipoprotein B deficiency
(abetalipoproteinemia)
a. Autosomal recessive
b. Deficiency of apolipoprotein B-48 and B-100
• (1) Deficiency of chylomicrons, VLDL and LDL
• (2) Decrease in serum CH and TG
c. Clinical findings
1) Malabsorption
a) Chylomicrons accumulate in villi and prevent
reabsorption of micelles.
b) Marked decrease in vitamin E
2) Ataxia (spinocerebellar degeneration),
hemolytic anemia with thorny RBCs
(acanthocytes) related to vitamin E deficiency.
d. Treatment - vitamin E
45.
46. OObbeessiittyy aann eexxcceessss ooff aaddiippoossee ttiissssuuee tthhaatt iimmppaarrttss hheeaalltthh
rriisskk;; aa bbooddyy wweeiigghhtt ooff 2200%% eexxcceessss oovveerr iiddeeaall wweeiigghhtt ffoorr aaggee,,
sseexx aanndd hheeiigghhtt iiss ccoonnssiiddeerreedd aa hheeaalltthh rriisskk..
BBooddyy mmaassss iinnddeexx ((BBMMII)) wwhhiicchh iiss eeqquuaall ttoo wweeiigghhtt iinn kkgg//hheeiigghhtt iinn mm22
• 1. Body mass index (BMI)
30kg/m2 (normal, 19.5-24.9kg/m2)
• 1) Excess fat in the waist and flanks is more
important than an excess in the thighs and
buttocks.
• 2) Excess visceral fat in the abdominal
cavity has greater significance than excess
subcutaneous fat.
• Magnetic resonance imaging is used to
access the amount of visceral fat.
50. Fat cell mass
[Leptin/insulin] expression
[Leptin/insulin] action in hypothalamus
NPY/AGRP
neurons
POMC/CART
neurons
NPY/AGRP
expression
Food intake
Sympathetic activity
α-MSH expression CART
and release
Arcuate nucleus
NPY release AGRP release
CCaattaabboolliissmm
α-MSH binding and
activation of melanocortin
MC4R receptors
FFoooodd iinnttaakkee
EEnneerrggyy eexxppeennddiittuurree
Paraventricular
nucleus
Leptin and insulin normally decrease appetite, increase satiety, and increase energy expenditure (catabolism).
Leptin/insulin inhibits NPY/AGRP gene expression resulting in decreased appetite and food intake; and
stimulates POMC/CART gene expression with resulting α-MSH release and decrease in appetite and food
intake. With leptin resistance as occurs in obesity, these effects are depressed and food intake increases in
excess of energy expenditure. AGRP, agouti-related peptide; α-MSH, alpha-melanocyte stimulating hormone;
NPY, neuropeptide Y; POMC/CART, proopiomelanocortin/cocaine-and-amphetamine-related transcript
51. Neuropeptide Y (NPY)
Melanin-concentrating
hormone (MCH)
Agouti-related protein
(AGRP)
Ghrelin
Galanin
Orexins A and B
Peptide YY (PYY)
Cortisol
Leptin
Insulin
Cholecystokinin (CCK)
Corticotropin-releasing
hormone (CRF)
Urocortin (a CRF satiety
signaling hormone)
Cocaine- and amphetamine-regulated
transcript (CART)
Alpha-melanocyte-stimulating
hormone (α-MSH)
Bombesin
Serotonin
Calcitonin
mmoolleeccuulleess tthhaatt ssttiimmuullaattee eeaattiinngg
molecules that inhibit eating
52. GGhhrreelliinn iiss pprroodduucceedd bbyy tthhee ssttoommaacchh iinn rreessppoonnssee ttoo hhuunnggeerr aanndd ssttiimmuullaatteess
ffoooodd iinnttaakkee aanndd iinndduucceess mmeettaabboolliicc cchhaannggeess lleeaaddiinngg ttoo aann iinnccrreeaassee iinn bbooddyy
wweeiigghhtt aanndd bbooddyy ffaatt mmaassss.. GGhhrreelliinn aallssoo ssttiimmuullaatteess rreelleeaassee ooff ggrroowwtthh
hhoorrmmoonnee ((GGHH)) ffrroomm aanntteerriioorr ppiittuuiittaarryy cceellllss,, tthhee rreelleeaassee ooff ggaassttrriicc aacciidd aanndd
ggaassttrriicc mmoottiilliittyy,, aanndd aaffffeeccttss ppaannccrreeaattiicc ffuunnccttiioonnss.. IItt hhaass vvaassooddiillaattoorryy,,
ccaarrddiioopprrootteeccttiivvee,, aanndd aannttiipprroolliiffeerraattiivvee eeffffeeccttss..
AAddiippoonneeccttiinn hhaass iinnssuulliinn--sseennssiittiizziinngg pprrooppeerrttiieess aanndd ppllaassmmaa lleevveellss ddeeccrreeaassee
wwiitthh vviisscceerraall oobbeessiittyy,, ccoonnttrriibbuuttiinngg ttoo iinnssuulliinn rreessiissttaannccee,, ccaarrddiioovvaassccuullaarr
ddiisseeaassee,, aanndd mmeettaabboolliicc ssyynnddrroommee..
OObbeessee iinnddiivviidduuaallss,, ppaarrttiiccuullaarrllyy tthhoossee wwiitthh eexxppaannssiioonn ooff vviisscceerraall aaddiippoossee
ttiissssuuee,, aarree aatt iinnccrreeaasseedd rriisskk ffoorr ccoorroonnaarryy aarrtteerryy ddiisseeaassee rreessuullttiinngg ffrroomm
hhyyppeerrlliippiiddeemmiiaa,, hhyyppeerrtteennssiioonn,, aanndd ffaaccttoorrss tthhaatt pprroommoottee tthhrroommbboossiiss aanndd
iinnffllaammmmaattiioonn..
Decreased adiponectin levels are associated with increased levels of
inflammatory markers, such as IL-6 and TNF-α.
Adiponectin may serve as an anti-inflammatory and anti-atherogenic
plasma protein and may have an important role in vascular remodeling that is
limited with obesity.
Obesity is associated with insulin resistance, which predisposes an
individual to type 2 diabetes mellitus. The insulin resistance may be related
to an insulin receptor defect or to postreceptor effects with alteration in
glucose transporter functions. Excess insulin also may be a response to
excessive caloric intake.
Resistin is greatly increased in those with obesity and may be an antagonist
to insulin action and a mediator of inflammation.
54. • 1. Hyperinsulinaemia. Increased
insulin secretion is a feature of
obesity. Many obese individuals exhibit
hyperglycaemia or frank diabetes
despite hyperinsulinaemia. This is due
to a state of insulin-resistance
consequent to tissue insensitivity.
• 2. Type 2 diabetes mellitus. There
is a strong association of type 2
diabetes mellitus with obesity. Obesity
often exacerbates the diabetic state and
in many cases weight reduction often
leads to amelioration of diabetes.
• 3. Hypertension. A strong
association between hypertension
and obesity is observed which is perhaps
due to increased blood volume. Weight
reduction leads to significant reduction
in systolic blood pressure.
55. 4. Hyperlipoproteinaemia. The plasma
cholesterol circulates in the blood as low-density
lipoprotein (LDL) containing most of
the circulating triglycerides. Obesity is strongly
associated with VLDL and mildly with LDL.
Total blood cholesterol levels are also
elevated in obesity.
5. Atherosclerosis. Obesity predisposes to
development of atherosclerosis. As a result
of atherosclerosis and hypertension, there is
increased risk of myocardial infarction and
stroke in obese individuals.
6. Nonalcoholic fatty liver disease
(NAFLD). Obesity contributes to
development of NAFLD which may progress
further to cirrhosis of the liver.
7. Cholelithiasis. There is six times higher
incidence of gallstones in obese persons,
mainly due to increased total body
cholesterol.
58. CCLLIINNIICCAALL FFIINNDDIINNGG CCOOMMMMEENNTTSS
CCaanncceerr Increased incidence of estrogen-related cancers (e.g., endometrial, breast)
because of increased aromatization of androgens to estrogens in adipose tissue
CChhoolleelliitthhiiaassiiss Increased incidence of cholecystitis and cholesterol stones: bile is
supersaturated with cholesterol
DDiiaabbeetteess mmeelllliittuuss,,
ttyyppee 22
Increased adipose downregulates insulin receptor synthesis
Hyperinsulinemia increases adipose stores
Weight reduction upregulates insulin receptor synthesis
HHeeppaattoommeeggaallyy Fatty change accompanied by liver cell injury and repair by fibrosis
HHyyppeerrtteennssiioonn
Hyperinsulinemia increases sodium retention, leading lo increase in plasma
volume
Left venlricular hypertrophy and stroke complicate hypertension
HHyyppeerrttrriiggllyycceerriiddeemmiiaa Hypertriglyceridemia decreases serum high-density lipoprotein levels,
increasing risk of coronary artery disease
IInnccrreeaasseedd llooww--ddeennssiittyy
lliippoopprrootteeiinn lleevveellss Hypercholesterolemia predisposes lo coronary artery disease
OObbssttrruuccttiivvee sslleeeepp
aappnneeaa
Weight of adipose tissue compresses upper airways causing respiratory
acidosis and hypoxemia
Potential for developing cor pulmonale (pulmonary hypertension and right
ventricular hypertrophy)
OOsstteeooaarrtthhrriittiiss Degenerative arthritis in weight-bearing joints (e.g., femoral heads)
59.
60.
61. PPrraaddeerr--WWiillllii ssyynnddrroommee (PWS) is a single gene imprinting disorder
(Psora/ Syphilis) caused by defects in chromosome 15. These defects
may be of two types:
1. Paternally inherited deletion or disruption of genes in the proximal arm
of chromosome 15. (Syphilis)
2. Maternal disomy in the proximal arm of chromosome 15. (Psora)
RReellaatteedd wwoorrddss
Cryptorchidism-dwarfism-subnormal mentality; hypogenital dystrophy
with diabetic tendency; hypotonia-hypomentia-hypogonadism-obesity
syndrome; Labhart-Willi syndrome; Prader-Labhart-Willi Fancone
syndrome; Willi-Prader syndrome.
HHiissttoorriiccaall BBaacckkggrroouunndd
The first patient with Prader-Willi syndrome was described by Langdon-Down In
1887 as an adolescent girl with mental impairment (Psora), short stature (Psora),
hypogonadism (Psora), obesity (Psora). He called these symptoms to polysarcia.
In 1956, Prader et al reported some patients with similar phenotypes.
In 1981, Ledbetter et al identified microdeletions (Syphilis) within chromosome 15
and determined it to be the site for Prader-Willi syndrome.
65. SPINGOLIPIDS. DISORDERS
Classes of sphingolipids and their hydrophilic groups include:
Sphingomyelin: phosphorylcholine
Cerebrosides: galactose or glucose
Gangliosides: branched oligosaccharide chains terminating
in the 9-carbon sugar, sialic acid (N-acetylneuraminic acid,
NANA)
Sphingolipids released when membrane is degraded are
digested in endosomes after fusion with lysosomes.
Lysosomes contain many enzymes, each of which removes
specific groups from individual sphingolipids. Genetic
deficiencies of many of these enzymes are known, and the
diseases share some of the characteristics of I-cell disease.
66. Disease Lysosomal
Enzyme Missing
Substrate
Accumulating in
Inclusion Body
Symptoms
Tay-Sachs Hexosaminidase A Ganglioside GM2 Cherry red spots in
macula; blindness
Gaucher Glucocerebrosidase Glucocerebroside
Type 1: Adult
Hepatosplenomegaly
Erosion of bones,
fractures; Pancytopenia or
thrombocytopenia;
Characteristic
macrophages (crumpled
paper inclusions)
Niemann-
Pick Sphingomyelinase Sphingomyelin
Cherry red spot in macula
Hepatosplenomegaly,
Microcephaly, severe
mental retardation; Zebra
bodies in inclusions;
Characteristic foamy
macrophages; Early death
67. The bright light at right enters through the pupil of the eye; at left,
the “red spot” in diagnosis of Tay-Sachs disease
Adult onset Niemann-Pick disease type C presenting with psychosis
68.
69. VViittaammiinn EEFFFFEECCTTSS OOFF DDEEFFIICCIIEENNCCYY EEFFFFEECCTTSS OOFF TTOOXXIICCIITTYY
AA
RReettiinnooll
Ocular lesions: night blindness, xerophthalmia - dry and
scaly scleral conjunctiva; keratomalacia - corneal ulcers
may occur which may get infected; Bitot’s spots - focal
triangular areas of opacities due to accumulation of
keratinised epithelium; blindness - squamous metaplasia
of corneal epithelium)
Cutaneous lesions: xeroderma - the skin develops
papular lesions giving toad-like appearance, due to
follicular hyperkeratosis and keratin plugging in the
sebaceous glands;
Other lesions: squamous metaplasia of respiratory
epithelium, pneumonia; urothelium and pancreatic ductal
epithelium, subsequent anaplasia; retarded bone growth;
renal calculi
Papilledema and seizures (due to
an increase In intracranial
pressure), hepatitis, bone pain (due
to periosteal proliferation)
DD
CCaallcciittrriiooll
Pathologic fractures, excess osteoid, bow legs
Children: rickets; craniotabes (soft skull bones); rachitic
rosary (defective mineralization and overgrowth of
epiphyseal cartilage in ribs)
Adults: called osteomalacia
Continuous muscle contraction (hypocalcaemic tetany)
Hypercalcemia with metastatic
calcification, renal calculi
70. VViittaammiinn EEFFFFEECCTTSS OOFF DDEEFFIICCIIEENNCCYY EEFFFFEECCTTSS OOFF TTOOXXIICCIITTYY
EEα
α--
TTooccoopphhee--
rrooll
Hemolytic anemia (damage to RBC membrane), reduced red cell
lifespan;
Peripheral neuropathy, degeneration of posterior column (poor joint
sensation) and spinocerebellar tract (ataxia), retinal pigments,
degeneration axons of peripheral nerves; denervation of muscles
Sterility in male and female animals
Decreased synthesis of
vitamin K-dependent
procoagulant factors;
synergistic effect with
warfarin anticoagulation
KK
Newborns: Hypoprothrombinaemia in hemorrhagic disease of newborn
(CNS bleeding, ecchymoses);
Adults: gastrointestinal bleeding, ecchymoses; prolonged prothrombin
time and partial thromboplastin time
biliary obstruction - bile is prevented from entering the bowel due to
biliary obstruction which prevents the absorption of this fat-soluble
vitamin. Surgery in patients of obstructive jaundice, therefore, leads to
marked tendency to bleeding.
malabsorption of fat develop vitamin K deficiency e.g. coeliac
disease, sprue, pancreatic disease, hypermotility of bowel etc.
anticoagulant therapy - patients on warfarin group of anticoagulants
have impaired biosynthesis of vitamin K-dependent coagulation factors.
antibiotic therapy - the use of broad-spectrum antibiotics and sulfa
drugs reduces the normal intestinal flora.
diffuse liver disease - (e.g. cirrhosis, amyloidosis of liver,
hepatocellular carcinoma, hepatoblastoma) have
hypoprothrombinaemia due to impaired synthesis of prothrombin.
Administration of vitamin K to such patients is of no avail since liver,
where prothrombin synthesis utilising vitamin K takes place, is
diseased.
Hemolytic anemia and
jaundice in newborns if
mother receives excess
vitamin K
71. 1. Copstead Lee-Ellen C. Pathophysiology / Lee-Ellen C. Copstead,
Jacquelyn L. Banasic // Elsevier Inc. – 2010.
2. ROBBINS BASIC PATHOLOGY / [edited by] Vinay Kumar, Abul K.
Abbas, Jon C. Aster. – 9th ed. – 2013.
3. Kathryn L. McCance . Pathophysiology: the biologic basis for disease in
adults and children / [edited by] Kathryn L. McCance, Sue E. Huether;
section editors, Valentina L. Brashers, Neal S. Rote - 6th ed. – 2010.
4. Pathophysiology, Concepts of Altered Health States, Carol Mattson
Porth, Glenn Matfin.– New York, Milwaukee. – 2009.
5. Essentials of Pathophysiology: Concepts of Altered Health States
(Lippincott Williams Wilkins), Trade paperback (2003) / Carol Mattson
Porth, Kathryn J. Gaspard. Chapters 15, 29.
6. General and clinical pathophysiology. Edited by prof. A.V. Kubyskin.
Simferopol. – 2011.
7. Silbernagl S. Color Atlas of Pathophysiology / S. Silbernagl, F. Lang //
Thieme. Stuttgart. New York. – 2000.
Notas do Editor
Essentially all of the energy of isometric contractions appears as heat, because little or no external work (force multiplied by the distance that the force moves a mass) is done. Energy is stored by forming energy-rich compounds. The amount of energy storage varies, but in fasting individuals it is zero or negative. Therefore, in an adult individual who has not eaten recently and who is not moving (or growing, reproducing, or lactating), all of the energy output appears as heat.
Calorimetry The energy released by combustion of foodstuffs outside the body can be measured directly (direct calorimetry) by oxidizing the compounds in an apparatus such as a bomb calorimeter, a metal vessel surrounded by water inside an insulated container. The food is ignited by an electric spark. The change in the temperature of the water is a measure of the calories produced. Similar measurements of the energy released by combustion of compounds in living animals and humans are much more complex, but calorimeters have been constructed that can physically accommodate human beings. The heat produced by their bodies is measured by the change in temperature of the water in the walls of the calorimeter. The caloric values of the common foodstuffs, as measured in a bomb calorimeter, are found to be 4.1 kcal/g of carbohydrate, 9.3 kcal/g of fat, and 5.3 kcal/g of protein. In the body, similar values are obtained for carbohydrate and fat, but the oxidation of protein is incomplete, the end products of protein catabolism being urea and related nitrogenous compounds in addition to CO2 and H2O (see below). Therefore, the caloric value of protein in the body is only 4.1 kcal/g. Indirect Calorimetry Energy production can also be calculated by measuring the products of the energy-producing biologic oxidations—ie, CO2, H2O, and the end products of protein catabolism produced—but this is difficult. However, O2 is not stored, and except when an O2 debt is being incurred, the amount of O2 consumption per unit of time is proportionate to the energy liberated by metabolism. Consequently, measurement of O2 consumption (indirect calorimetry) is used to determine the metabolic rate. Respiratory Quotient (RQ) The respiratory quotient (RQ) is the ratio in the steady state of the volume of CO2 produced to the volume of O2 consumed per unit of time. It should be distinguished from the respiratory exchange ratio (R), which is the ratio of CO2 to O2 at any given time whether or not equilibrium has been reached. R is affected by factors other than metabolism. RQ and R can be calculated for reactions outside the body, for individual organs and tissues, and for the whole body. The RQ of carbohydrate is 1.00, and that of fat is about 0.70. This is because H and O are present in carbohydrate in the same proportions as in water, whereas in the various fats, extra O2 is necessary for the formation of H2O. Determining the RQ of protein in the body is a complex process, but an average value of 0.82 has been calculated. The approximate amounts of carbohydrate, protein, and fat being oxidized in the body at any given time can be calculated from the RQ and the urinary nitrogen excretion. RQ and R for the whole body differ in various conditions. For example, during hyperventilation, R rises because CO2 is being blown off. During severe exercise, R may reach 2.00 because CO2 is being blown off and lactic acid from anaerobic glycolysis is being converted to CO2 (see below). After exercise, R may fall for a while to 0.50 or less. In metabolic acidosis, R rises because respiratory compensation for the acidosis causes the amount of CO2 expired to rise. In severe acidosis, R may be greater than 1.00. In metabolic alkalosis, R falls. The O2 consumption and CO2 production of an organ can be calculated at equilibrium by multiplying its blood flow per unit of time by the arteriovenous differences for O2 and CO2 across the organ, and the RQ can then be calculated. Data on the RQ of individual organs are of considerable interest in drawing inferences about the metabolic processes occurring in them. For example, the RQ of the brain is regularly 0.97-0.99, indicating that its principal but not its only fuel is carbohydrate. During secretion of gastric juice, the stomach has a negative R because it takes up more CO2 from the arterial blood than it puts into the venous blood
Large animals have higher absolute BMRs, but the ratio of BMR to body weight in small animals is much greater. One variable that correlates well with the metabolic rate in different species is the body surface area. This would be expected, since heat exchange occurs at the body surface. The actual relation to body weight (W) would be However, repeated measurements by numerous investigators have come up with a higher exponent, averaging 0.75. Thus, the slope of the line relating metabolic rate to body weight is steeper than it would be if the relation were due solely to body area. The cause of the greater slope has been much debated but remains unsettled.
For example, catabolism of 1 mol of a six-carbon fatty acid through the citric acid cycle to CO2 and H2O generates 44 mol of ATP, compared with the 38 mol generated by catabolism of 1 mol of the six-carbon carbohydrate glucose.
Two of the three ketone bodies, acetoacetate and β-hydroxybutyrate, are anions of the moderately strong acids acetoacetic acid and β-hydroxybutyric acid. Many of their protons are buffered, reducing the decline in pH that would otherwise occur. However, the buffering capacity can be exceeded, and the metabolic acidosis that develops in conditions such as diabetic ketosis can be severe and even fatal. Three conditions lead to deficient intracellular glucose supplies: starvation, diabetes mellitus, and a high-fat, low-carbohydrate diet. In diabetes, glucose entry into cells is impaired. When most of the caloric intake is supplied by fat, carbohydrate deficiency develops because there is no major pathway for converting fat to carbohydrate. The liver cells also become filled with fat, which damages them and displaces any glycogen that is formed. In all of these conditions, ketosis develops primarily because the supply of ketones is overabundant. The acetone odor on the breath of children who have been vomiting is due to the ketosis of starvation. Parenteral administration of relatively small amounts of glucose abolishes the ketosis, and it is for this reason that carbohydrate is said to be antiketogenic.
http://www.theatlantic.com/health/archive/2013/03/study-mummies-have-atherosclerosis-too/273863/
http://blogs.unimelb.edu.au/sciencecommunication/2013/08/13/mummies-return-is-a-reality-we-need-more-mummy-hunters/
Put more colorfully, &quot;We found that heart disease is a serial killer that has been stalking mankind for thousands of years,&quot; one of the study&apos;s lead authors, Randall Thompson, said in a statement.
In modern men and women over the age of 50, the condition&apos;s prevalence is as high as 82 and 68 percent, respectively. And certain behaviors certainly increase this risk -- these findings in fact emphasize the importance of controlling for those factors, like diet, that are indeed controllable. As with last summer&apos;s counter-intuitive findings that sedentary office workers burn as many calories in a day as modern hunter-gatherers, this should at the very least make us question whether the good old days of pre-modern living were as ideal as we tend to imagine them.
Dyslipidemia (or dyslipoproteinemia) refers to abnormal concentrations of serum lipoproteins as defined by the Third Report of the National Cholesterol Education Program. It is estimated that nearly half of the U.S. population has some form of dyslipidemia, especially among white and Asian populations. These abnormalities are the result of a combination of genetic and dietary factors.
Primary or familial dyslipoproteinemias result from genetic defects that cause abnormalities in lipid-metabolizing enzymes and abnormal cellular lipid receptors.
Secondary causes of dyslipidemia include several common systemic disorders, such as diabetes, hypothyroidism, pancreatitis, and renal nephrosis, as well as the use of certain medications such as certain diuretics, beta-blockers, glucocorticoids, interferons, and antiretrovirals.
Physical signs of heterozygous familial hypercholesterolemia (HeFH), which result from cholesterol deposited within macrophages in specific sites. Tendinous xanthomas, for example, manifest first as thickening of, and later as deposits within, extensor tendons. A: Lateral borders of thickened Achilles&apos; tendons are shown with arrows. B: Tendinous xanthomas can also occur in the extensor tendons of the hands (shown), feet, elbows and knees. C: Xanthelasmas are cholesterol deposits in the eyelids. D: Arcus cornealis results from cholesterol infiltration around the corneal rim (arrow). Deposits in and around the eye tend to be more specific for HeFH in people younger than 45 years; in elderly people, they are less likely to be associated with blood lipoprotein abnormalities, for instance in the case of arcus senilis.
Some patients may report having observed cutaneous cholesterol deposition in response to a functional enquiry. People with HeFH have been known to undergo cosmetic eyelid surgery to remove xanthelasmas — even repeatedly, for lesions that continued to recur — without ever having had their plasma lipoprotein profiles determined.
Obesity is a problem because of its complications. It is associated with accelerated atherosclerosis and an increased incidence of gallbladder and other diseases. Its association with type 2 diabetes is especially striking. As weight increases, insulin resistance increases and frank diabetes appears. At least in some cases, glucose tolerance is restored when weight is lost.The causes of the high incidence of obesity in the general population are probably multiple. Studies of twins raised apart show that there is a definite genetic component. It has been pointed out that through much of human evolution, famines were common, and mechanisms that permitted increased energy storage as fat had survival value. Now, however, food is plentiful in many countries, and the ability to gain and retain fat has become a liability. As noted above, the fundamental cause of obesity is still excess of energy intake in food over energy expenditure. If human volunteers are fed a fixed high-calorie diet, some gain weight more rapidly than others, but the slower weight gain is due to increased energy expenditure in the form of small, fidgety movements (nonexercise activity thermogenesis; NEAT). Body weight generally increases at a slow but steady rate throughout adult life. Decreased physical activity is undoubtedly a factor in this increase, but decreased sensitivity to leptin may also play a role.
PATHOGENESIS. The lipid storing cells, adipocytes comprise the adipose tissue, and are present in vascular and stromal compartment in the body. Besides the generally accepted role of adipocytes for fat storage, these cells also release endocrine-regulating molecules. These molecules include: energy regulatory hormone (leptin), cytokines (TNF-α and interleukin-6), insulin sensitivity regulating agents (adiponectin, resistin and RBP4), prothrombotic factors (plasminogen activator inhibitor), and blood pressure regulating agent (angiotensingen).
Adipose mass is increased due to enlargement of adipose cells due to excess of intracellular lipid deposition as well as due to increase in the number of adipocytes. The most important environmental factor of excess consumption of nutrients can lead to obesity. However, underlying molecular mechanisms of obesity are beginning to unfold based on observations that obesity is familial and is seen in identical twins. Recently, two obesity genes have been found: ob gene and its protein product leptin, and db gene and its protein product leptin receptor.
Obesity is the most common and most expensive nutritional problem in the USA. A convenient and reliable indicator of body fat is the body mass index (BMI), which is the body weight (in kilograms) divided by the square of the height (in meters). Values above 25 are abnormal. Individuals with values of 25-30 are overweight, and those with values &gt; 30 are obese. In the USA, 55% of the population are overweight and 22% are obese. The incidence of obesity is also increasing in other countries. Indeed, the Worldwatch Institute has estimated that although starvation continues to be a problem in many parts of the world, the number of overweight people in the world is now as great as the number of underfed.