Massive Hypertriglyceridaemia: A complete white-out, O. B OxLDL IDL B E CIII VLDL B E CIII -100 LPL...
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Transcript of Massive Hypertriglyceridaemia: A complete white-out, O. B OxLDL IDL B E CIII VLDL B E CIII -100 LPL...
Massive Hypertriglyceridaemia: A complete white-out,
O.
BOxLDL
IDL
B
ECIII
VLDL
B
ECIII
-100
LPL
BLDL
HL
FCAI
AII
INTESTINE
B
Chy
lom
icro
ns
CII
-48
AI
LIVERLDL-R
LRP
Macrophage
Lox-1
CD-36SR-A
SR-PSOXABCA1
SR-B1CE+FC CE
TG
CETPAI
AII
EHDL
LCATFC
CE
Other tissues
LPLR
E
B
CII
FC
LCAT
FC
CE
DAVIGNON 2006
Metabolic RelationshipsAmong Lipoproteins
LDL
1.
3.
2.
LipoproteinLipase`
TGHDL
VLDL
TRIGLYCERIDES
HDL SMALLDENSE LDL
Chylomicrons and their remnants may be less likely to cause atherosclerosis
(smaller numbers and larger size)
FATTYACIDS
(ALBUMIN)
TG (VLDL)
TG (CHYLO-MICRONS)
LIPO-PROTEIN
LIPASE
Fatty Acid and Triglyceride Flux
Pancreatic Lipase Movement
Most pancreatic lipase is secreted into the pancreatic duct, but some moves back into capillaries.
Most pancreatic lipase is secreted into the pancreatic duct, but some moves back into capillaries.
Chylomicron Role in Pancreatitis
Pancreatic lipase actson chylomicrons adherent to capillaryendothelium, producingfatty acid anions, or soaps. By detergentaction, cell membranesare disrupted, releasingmore lipase, and additional fatty acidanions are produced ina vicious cycle.
Pancreatic lipase actson chylomicrons adherent to capillaryendothelium, producingfatty acid anions, or soaps. By detergentaction, cell membranesare disrupted, releasingmore lipase, and additional fatty acidanions are produced ina vicious cycle.
Dietary management of lipoprotein lipase deficiency: Avoid dietary fat, except MCT’s and marine oil n-3
fatty acids
Other treatment options in lipoprotein lipase deficiency
• Fibrates and marine oil n-3 fatty acids: limitation of gene response
• Avoid insulin deficiency: Cofactor for lipoprotein lipase
• Temporary effect of plasmapheresis
• Temporary effect of plasma transfusion in apo C2 (cofactor) deficiency
• ? Xenical
• Future: DGAT1 inhibitors
• ?Gene therapy
■ Normal■ Hypoalpha- lipoproteinemia
■ Complete (FHC) or partial LPL deficiency associated with a secondary factor
■ Complete LPL deficiency (FHC)■ Primary apoC-II deficiency
■ Familial dysbeta- lipoproteinemia (type III)■ Hepatic lipase deficiency■ (Primary cause associated with a secondary factor)
Apo B > 0.75 g/L
Apo B < 0.75 g/L
TC:Apo B > 6.2
TC:Apo B < 6.2
■ Familial hyperTG■ Partial LPL deficiency
■ FH■ Polygenic■ FDB■ PCSK9deficiency■ ARH deficiency■ CYP7A1deficiency■ Hypoalphalipo-proteinemia
■ FCH■ β-Sitosterolemia
Normal Chylo + VLDL Chylo Chylo +
VLDL Remnants
VLDL LDL VLDL + LDL
NormoTG< 1.5
mmol/L
TG:Apo B > 0.12
NormoApo B< 1.2 g/L
TG:Apo B < 0.12
HyperTG> 1.5
mmol/L
NomoTG> 1.5
mmol/L
HyperApo B> 1.2 g/L
Hyper TG> 1.5
mmol/L
PrimaryCauses
Algorithm for Diagnosis of Apo B DyslipoproteinemiasAlgorithm for Diagnosis of Apo B Dyslipoproteinemias
Abbreviations: apo, apolipoprotein; ARH, autosomal recessive hypercholesterolemia; CAPD, continuous ambulatory peritoneal dialysis; Chylo, chylomicrons; CP7A1, cytochrome P450 7A1; DM2, diabetes mellitus type 2; dysbeta; dysbetalipoproteinemia; FCH, familial combined hyperlipidemia; FDB, familial defective apoB; FH, familial hypercholesterolemia; FHC, familial hyperchylomicronemia; HAART, highly active antiretroviral therapy; LPL, lipoprotein lipase; PCOS, polycystic ovary syndrome; SLE, systemic lupus erythematosus; TC, total cholesterol; TG, triglyceride. de Graaf J et al. Nat Clin Pract Endocrinol Metab 2008;4:608-
18.
Lipoproteins
Nordestgaard BG, et al. JAMA. 2007;298(3):299-308
Relationship of Non-Fasting Triglycerides and Cardiovascular Risk
Copenhagen City Heart Study(7587 women and 6394 men)
Bansal S, et al. JAMA. 2007;298(3):309-316
Relationship of Non-Fasting Triglycerides and Cardiovascular Risk
Womens Health Study (n= 26,509)
Nordestgaard BG, et al. JAMA. 2007;298(3):299-308
Relationship of Non-Fasting Triglycerides and Cardiovascular Risk
Copenhagen City Heart Study(7587 women and 6394 men)
Rx and response
Fibrates and marine oil n-3 fatty acids: greater prospect of gene upregulation
Niacin: greater prospect of gene upregulation
Avoid insulin deficiency: Cofactor for lipoprotein lipase
Temporary effect of plasmapheresis
? Xenical
Future: DGAT1 inhibitors
COOH
C20:5 ω-3 Eicosapentaenoic(EPA)
H3C
Essential Fatty Acid Families
C18:3 ω-3
ω-3 family
-Linolenic• Flaxseed Oil• Canola Oil• Soybean Oil
C22:6 ω-3 Docosahexaenoic(DHA)
COOHH3C
• Oily Fish• Fish Oil
Capsules
H3CCOOH
ω-6 family
C20:4 ω-6
C18:2 ω-6 Linoleic
Arachidonic
H3CCOOH
More thrombotic and inflammatory metabolites
• Corn Oil• Safflower Oil• Sunflower Oil
Less thrombotic and inflammatory metabolites
H3C COOH
What happens in the food chain?:
Starting materials
Modification by herbivores
Accumulation by carnivores
Essential Fatty Acid Contrasts: Position of 1st double bond
N-6 :
– Greater availability in diet
– Greater availability in membranes.
– Main substrate for PG & LT
– Typical inflammatory response
N-3:
– Lower availability, so lesser substrate for PG & LT
– Highest potential number of double bonds.
– Less inflammatory response
Essential Fatty Acid Contrasts: Chain length
N-3 < 20C (Plant):
– Too short for membrane Phosphlipid
– Full effect as anti-arrhythmic
– No effect on TG
– No effect on platelet adhesion
– Effective precursor
N-3 > C20 (Marine)
– Suitable for membrane Phospholipid
– Strongly anti- arrhythmic
– Reduce TG synthesis and decrease TG by about 50%
– Reduce platelet adhesion.
Postprandial Lipoproteins affect FMD after Oral Fat Load
Franco M et al. J Clin Endo & Metab 2004;89:2946-2950
0h 2h 4h 6h 8h
0h 2h 4h 6h 8h
0h 2h 4h 6h 8h2
3
4
5
6
7
10
12
14
16
18
0.4
0.7
0.8
0.9
1.0
0.6
0.5
mm
ol/L
% D
ilati
onm
mol
/L
FMD
Remnant-C
Triglycerides TG & RLP-C increased significantly and continuously up to 4 & 6 hours respectively
FMD revealed decreased vasodilation at 4-6 hours
Results vary, but postprandial events, including secretion of chylomicrons, exert strong effects on vascular function
Mrs N.S.• This 36 year old woman has not been able to conceive. She gained a large
amount of weight (BMI 38) when she stopped smoking in her mid 20’s. Unfortunately she resumed smoking in her early 30’s without any change in weight. Alcohol intake is less that 30 gms / week. Two years ago she became diabetic and now requires insulin to maintain HB A1C < 7.5%. Even then, associated lipid levels include triglyceride of 38 mmol/l, but she has not suffered pancreatitis.
Questions concerning Mrs N.S.
• What priority do you place on cessation of smoking in this case?
High / Low
• Your preferred strategy to achieve weight loss involves the use of A) Xenical B) Meal replacement C) gastric bypass D) Metformin
• If symptoms suggested the onset of an attack of pancreatitis, appropriate immediate intervention would include: A) Nil by mouth B) Consideration of plasmapheresis, C) Commencement of statin therapy D) Reduction in Insulin dose E) All of the above
• What priority do you place on cessation of smoking in this case?
High / Low
• Your preferred strategy to achieve weight loss involves the use of A) Xenical B) Meal replacement C) gastric bypass D) Metformin
• If symptoms suggested the onset of an attack of pancreatitis, appropriate immediate intervention would include: A) Nil by mouth B) Consideration of plasmapheresis, C) Commencement of statin therapy D) Reduction in Insulin dose E) All of the above
This 36 year old woman has not been able to conceive. She gained a large amount of weight (BMI 38) when she stopped smoking in her mid 20’s. Unfortunately she resumed smoking in her early 30’s without any change in weight. Alcohol intake is less that 30 gms / week. Two years ago she became diabetic and now requires insulin to maintain HB A1C < 7.5%. Even then, associated lipid levels include triglyceride of 38 mmol/l, but she has not suffered pancreatitis.
What priority do you place on cessation of smoking in this case?
A vexed problem. Theoretical reasons for “high”
Your preferred strategy to achieve weight loss involves the use of ...
• A) Xenical
• B) Meal replacement
• C) gastric bypass
• D) Metformin
If symptoms suggested the onset of an attack of pancreatitis, appropriate immediate
intervention would include
• A) Nil by mouth
• B) Consideration of plasmapheresis,
• C) Commencement of statin therapy
• D) Reduction in Insulin dose
• E) All of the above
If symptoms suggested the onset of an attack of pancreatitis, appropriate immediate
intervention would include...Pattern of the problem (a case for “A”)
Mrs N.S.• Although advice about diet and smoking fails to alter weight or glycaemic
control, your introduction of fenofibrate and fish oil reduces TG to 17 mmol/l. Mrs N.S. desperate to start a family and is actively pursuing IVF.
• Is the decline in TG to 17 mmol/l sufficient to eliminate the risk of acute pancreatitis? Yes / No
• Do reproductive hormones like oestrogen and progesterone, IVF therapies or pregnancy itself affect triglyceride levels or risk of pancreatitis?
Yes / No
• Would you continue fenofibrate? Yes / No
• Your estimate on Mrs N.S’s risk of a cardiovascular event is:
A) Low now and in the future
B) Low now, but high in the future
C) High, even now.
Is the decline in TG to 17 mmol/l sufficient to eliminate the risk of acute
pancreatitis?
• Yes
• No
Is the decline in TG to 17 mmol/l sufficient to eliminate the risk of acute
pancreatitis? The case for “no”
TG in mg%For mmol/lDivide by 90
Do reproductive hormones like oestrogen and progesterone, IVF therapies or pregnancy itself affect triglyceride levels or the risk of
pancreatitis?
• Yes
• No
Do reproductive hormones like oestrogen and progesterone, IVF therapies or pregnancy
itself affect triglyceride levels? The case for “yes”
Obstet Gynecol. 1993 May;81(5 ( Pt 2)):890-2.Recurrent pancreatitis associated with in vitro fertilization.Steinmetz OK, Hashim E, Falcone T, Hemmings R, Bourque J.BACKGROUND:We report the possible association between in vitro fertilization (IVF) and recurrent acute pancreatitis.CASE:A patient developed acute pancreatitis during each of two cycles of IVF. On a spontaneous cycle, serum triglycerides were as follows: early follicular phase 2.34 mmol/L, mid-follicular phase 4.17 mmol/L, and late follicular phase 6.6 mmol/L. During an episode of acute pancreatitis, the serum triglyceride level was 38.45 mmol/L.CONCLUSION:Acute pancreatitis may occur in patients with a family or personal history of hypertriglyceridemia who are candidates for IVF.
Would you continue fenofibrate?Uncertain teratogenicity versus
manifest risk.
Pregnancy: Teratogenic Effects, Pregnancy Category CSafety in pregant women has not been established. Fenofibrate has been shown to be embryocidal and teratogenic in rats when given in doses 7 to 10 times the maximum recommended human dose (MRHD) and embryocidal in rabbits when given at 9 times the MRHD (on the basis of mg/meter2 surface area). There are no adequate and well-controlled studies in pregnant women. Fenofibrate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus
Your estimate on Mrs N.S’s risk of a cardiovascular event is:
A) Low now and in the future
B) Low now, but high in the future
C) High, even now.
Mr G.T.• Mr G.T. is 32 years old. He is Chinese and he consumes an Asian diet. He is
not overweight, but his business and social obligations involve occasional Asian banquets. He rarely drinks more than 20 gms alcohol per week. He suffered occasional episodes of abdominal pain in adolescence and early adulthood, and recently he was admitted to an intensive care unit with his first episode of acute pancreatitis. Fasting plasma lipids included plasma triglyceride level of 56 mmol/l but plasma glucose is within normal limits.
Questions concerning Mr G.T.
• What physical findings might accompany an episode of this severity?(More than 1 possible) A) Tendon Xanthomas B) Lipaemia Retinalis C) Tuberous Xanthomas D) Eruptive Xanthomas E) Corneal Arcus
• How would you investigate the possibility of lipoprotein lipase (LPL) deficiency? A) Plasma LPL mass B) Plasma LPL activity C) Plasma LPL activity after a heparin bolus D) Protein iso-electric focussing for Apo C3 E) Genetic testing
• What diet advice would you give on discharge? A) Low fat diet < 10% energy B) Medium chain triglycerides to minimumize carbohydrate C) Extra fish oil (>15 gms) D) All of the above E) Low fat diet < 25% energy
• Mr G.T. is 32 years old. He is Chinese and he consumes an Asian diet. He is not overweight, but his business and social obligations involve occasional Asian banquets. He rarely drinks more than 20 gms alcohol per week. He suffered occasional episodes of abdominal pain in adolescence and early adulthood, and recently he was admitted to an intensive care unit with his first episode of acute pancreatitis. Fasting plasma lipids included plasma triglyceride level of 56 mmol/l but plasma glucose is within normal limits.
• What physical findings might accompany an episode of this severity?(More than 1 possible) A) Tendon Xanthomas B) Lipaemia Retinalis C) Tuberous Xanthomas D) Eruptive Xanthomas E) Corneal Arcus
• How would you investigate the possibility of lipoprotein lipase (LPL) deficiency? A) Plasma LPL mass B) Plasma LPL activity C) Plasma LPL activity after a heparin bolus D) Protein iso-electric focussing for Apo C3 E) Genetic testing
• What diet advice would you give on discharge? A) Low fat diet < 10% energy B) Medium chain triglycerides to minimumize carbohydrate C) Extra fish oil (>15 gms) D) All of the above E) Low fat diet < 25% energy
What physical findings might accompany an episode of this severity? (More than 1 possible)
• A) Tendon Xanthomas
• B) Lipaemia Retinalis
• C) Tuberous Xanthomas
• D) Eruptive Xanthomas
• E) Corneal Arcus
What physical findings might accompany an episode of this severity? (More than 1 possible)
The case for “B” and “D”
How would you investigate the possibility of lipoprotein lipase (LPL) deficiency?
• A) Plasma LPL mass
• B) Plasma LPL activity
• C) Plasma LPL activity after a heparin bolus
• D) Protein iso-electric focussing for Apo C3
• E) Genetic testing
How would you investigate the possibility of lipoprotein lipase (LPL) deficiency? The case
for “C”, but “E” is becoming possible
What diet advice would you give Mr G.T. on discharge?
• A) Low fat diet < 10% energy
• B) Medium chain triglycerides to minimize carbohydrate
• C) Extra fish oil (>10 gms/day)
• D) All of the above
• E) Low fat diet < 25% energy
More questions about Mr G.T.• Despite your dietary advice, Mr G.T. suffers a recurrence of pancreatitis 5
months later.
• When massive hypertriglyceridaemia is present, which of the following symptoms may occur? A) Risk of pancreatitis, Abdominal pain, hepatosplenomegaly B) Confusion C) Peripheral paresthesiasD) Dyspnea E) All of the above
• If lipoprotein lipase deficiency is confirmed, what treatment options would you suggest? A) Continuation of current diet B) Gene therapy C) Total pancreatectomy plus pancreatic transplant D) Biliary diversion E) Plasmapheresis
When massive hypertriglyceridaemia is present, which of the following
symptoms may occur?
A) Risk of pancreatitis, Abdominal pain, hepatosplenomegaly
B) Confusion
C) Peripheral paresthesias
D) Dyspnea
E) All of the above
When massive hypertriglyceridaemia is present, which of the following symptoms
may occur? The case for “E”.
Accumulated case reports, eg “He reported recurrent headachesand dizziness with lightheaddedness and vertigoindependently of alcohol consumption. Thesesymptoms were accompanied by mood disturbancesincluding dysphoria and depression. Neurologicexamination was normal.
If lipoprotein lipase deficiency is confirmed, what treatment options would you suggest?
• A) Continuation of current diet
• B) Gene therapy
• C) Total pancreatectomy plus pancreatic transplant
• D) Biliary diversion
• E) Plasmapheresis