Hypothesis: AN ECTOPIC SYNTHESIS OF THE MELANIN IN ADIPOSE MAY HELP TO COUNTERACT SECONDARY...
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Transcript of Hypothesis: AN ECTOPIC SYNTHESIS OF THE MELANIN IN ADIPOSE MAY HELP TO COUNTERACT SECONDARY...
Hypothesis: AN ECTOPIC SYNTHESIS OF THE MELANIN IN ADIPOSE
MAY HELP TO COUNTERACT SECONDARY COMPLICATIONS OF OBESITY
Manpreet Randhawa, Tom Huff, Julio C. Valencia, Zobair Younossi, Vikas Chandhoke, Vincent J. Hearing, Ancha Baranova
Why obesity is so dangerous ?
whyfiles.org/276metabolic_syndrome/
METABOLIC SYNDROME
Common complications :
Cardiovascular diseasesDiabetes type II
Non-alcoholic fatty liver disease (NAFLD)Non-alcoholic steatohepatitis (NASH)
Prevalence of the metabolic syndrome increases with age National Health and Nutrition Examination Survey III, 1988-1994
(8814 US adults)
Males
Females
Prevalence of metabolic syndrome increases with obesity
, blacks; , Hispanics; , whites.
U.S. INCIDENCE OF DIABETES (BOTH TYPES): CDC graph
Cost burden of obesity (U.S. only)
Direct cost only; 17% of total direct cost of heart disease, independent of stroke
Direct and indirect costs
Direct and indirect costs
Direct cost only; 17% of total direct cost of hypertension
Health-Care Costs for Obesity Top Those Related to Smoking
Obesity is associated with an average increase in hospital and outpatient spending of $395 a year
There has definitely been a feeling that smoking, drinking and
substance abuse are bigger problems
than obesity. This isn't the case.
Males
Females
Prevalence of metabolic syndrome increases with obesity
, blacks; , Hispanics; , whites.
Some obese people stay healthy
despite very high BMI(even within bariatric cohort)
WHY?
Glass half full or half empty?
Non-Alcoholic Liver Disease as a model
for the study of the secondary complications of obesity
From: Ariel E. Feldstein and Marsha H. Kay, ACG website
The majority of individuals with NAFLD have no symptoms and a normal examination
NAFLD affects up to 20 % of adults and nearly 5 % of children.
NASH 2-5 % of adult Americans; up to 20 % of obese subjects.
Can we treat NAFLD ? Not really. Just try to lose weight….
increased risk of hepatocellular carcinoma
Liver transplantation Fibrosis
For these who thinks that fat in the liver is microscopic change
IMPORTANT QUESTION: WHY SOME PATIENTS WITH VERY HIGH BMI (>45)
STAY FREE OF LIVER DISEASE?
ARE SOME PROTECTIVE FACTORS OR PREDISPOSING FACTORS INVOLVED?
ARE THESE FACTORS PRESENT IN THE LIVER OR IN THE FAT?
Results of the visceral adipose profiling
(40K chip)
Results of the Liver biopsy profiling (5K chip)
Dataset was downsized
> 2.0 in the liver (NASH vs OC)= pro-NASH genes in the liver
< 0.5 in the liver (NASH vs OC)= hepatoprotective genes in the liver
> 2.0 in the adipose (NASH vs OC)= pro-NASH genes in the fat
< 0.5 in the adipose (NASH vs OC)= hepatoprotective genes in the fat
Obese Patients with NASH
vsObese patients
without liver pathology
TNF-α and IL6 regulated genes expressed in adiposeplay a prominent role in the development of NASH
Genes that are regulated by TGF-β signal
in adipose are important for the development
of the primary phenotype
of the morbid obesity
Major finding: Adipose of the NASH patients
overexpresses a number of genes encoding secreted,
mostly pro-inflammatory molecules. IL18 interleukin 18 (interferon-gamma-inducing factor)
CCL26 chemokine (C-C motif) ligand 26
CCL20 chemokine (C-C motif) ligand 20
CTSB cathepsin B
B2M beta-2-microglobulin
UMOD uromodulin (uromucoid, Tamm-Horsfall glycoprotein)
PROC protein C (inactivator of coagul. factors Va and VIIIa)
FCN1 ficolin (collagen/fibrinogen domain containing) 1
CLU clusterin (complement lysis inhibitor, apolipoprotein J)
F3 coagulation factor III (thromboplastin, tissue factor)
Other cells embedded in adipose, including macrophages
Visfatin, Vaspin, Apelin, PAI-1, MCP1, other pro-inflammatory molecules
IL-6 IL-8
NAFLD and NASH develop under the influence
of the adipokines synthetized in the visceral adipose
ANOTHER study: Profiling of adiponectin, resistin,
visfatin, apelin, TNF-alpha, IL-6, IL-8, IL1, IL1R, sIL-6
in the serum of patients with and without NAFLD
100 samples collected and profiled;
Correlation analysis with seven clinical parameters is completed;
Visfatin TNF-α
IL-8 IL-6C. D.
Controls I(N=38)
Controls II(N=12)
NAFLD (N=45)
SS (N=19)
NASH (N=26)
Me
an
(p
g/m
l)
Controls I(N=38)
Controls II(N=12)
NAFLD (N=45)
SS (N=19)
NASH (N=26)
1
10
100
1000
A.
Me
an
(p
g/m
l)
100
B.M
ea
n (
pg
/ml)
Controls I(N=38)
Controls II(N=12)
NAFLD (N=45)
SS (N=19)
NASH (N=26)
100100
10
11
Controls I(N=38)
Controls II(N=12)
NAFLD (N=45)
SS (N=19)
NASH (N=26)
Me
an
(p
g/m
l)
10
1000
100
TNF-α
Controls I(N=38)
Controls II(N=12)
NAFLD (N=45)
SS (N=19)
NASH (N=26)
Me
an
(p
g/m
l)
10
1000
B.
100
TNF-α, pg/ml
Obese Healthy (N = 38)
1.91+/-0.25
Lean Healthy (N = 12)
2.3+/-0.39 < 0.0001
Lower than normal levels of TNF-αmay prevent the onset of NAFLD
in morbidly obese patients.
*
General Theme: Visceral fat in some obese subjects
remains inert; Something protects obese people with
inert fat from metabolic syndrome
Expression profiling in human OBESITY
• Comparisons of the visceral fat samples;
• >50 patients sampled during bariatric surgeries;
• 9 lean peoples donating their kidney;
Fat Tissue
Stratagene human Ref. RNA
Isolate total RNA
Reverse Transcribe tocDNA, label with Cy3
Reverse Transcribe to cDNA, label with Cy5
Mix, Hybridize and Scan
Linearly Amplify RNA Linearly Amplify RNA
METHOD :
Four comparisons were performed:
• Morbidly obese (N=50) vs. Controls
• Diabetic obese vs. normoglycemic obese
– No significant genes found
• Diabetic obese (N= 9) vs. Controls
• NormoGlycemic Obese (N=22) vs. Controls
DMO = Obese with diabetes; MO =Obese without diabetes;
NGO = NormoGlycemic Obese
All comparison were performed
vs. Non-Obese Controls
A LIST OF MELANOGENESIS RELATED GENES DIFFERENTIALLY
EXPRESSED IN OBESE ADIPOSE• Genes fold difference Accession number
TYRP1 2.66 AA668457
DCT 2.17 N27147
RAB27A 2.47 AI309109
RAB27B 2.6 R39044
MITF 1.5 N67822
SOX 1.36 AA976578
CHS1 1.22 N74383
Tyrosinase itself was not present on the chip
Expression of TYR, TYRP1 and DCT in lean and obese adipose samples
0
20
40
60
80
100
120
140
TYR DCT TYRP1
Re
lati
ve
ex
pre
ss
ion
un
its
Lean Adipose
Obese Adipose
Expression of TYR, TYRP1 and DCT in adipose tissue as revealed by
Quantitative RealTime-PCR
P < 0.007 P< 0.024 NS
Fontana-Masson stain of human adipose tissue demonstrates melanin pigment (black staining) mainly
in the periphery of the adipocytes.
Cryoslicing of visceral adipose
Melanin detection Fontana-Masson kit