advanced glycation end products in diabetic kidney disease
DESCRIPTION
Advanced Glycation End Products in Diabetic Kidney Disease. Grishma Parikh, MD Mount Sinai School of Medine 5 th Annual Friedman Fellows Symposium 11/17/2012. AGEs. Advanced Glycation End products (AGEs) Formed by non-enzymatic glycosylation of proteins and lipids - PowerPoint PPT PresentationTRANSCRIPT
Advanced Glycation End Products in Diabetic Kidney
Disease
Grishma Parikh, MDMount Sinai School of Medine
5th Annual Friedman Fellows Symposium11/17/2012
AGEs
• Advanced Glycation End products (AGEs)– Formed by non-enzymatic glycosylation of
proteins and lipids– Potent inducers of inflammation and ROS– Source: • Exogenous : Food and Cigarettes• Endogenous : Normal metabolism and Aging
– Excess: Linked to major chronic diseases
333H.Vlassara: Annals of Medicine, 2008
Glucose+Proteins
LipidsRNA/DNA
A
HO· ROS B
RO·
C
HbA1c
Formation of AGEs (Oxidants)
AGEs toxicity is due both to the release of ROS and alterations of proteins and lipids.
AGEs
MG CMLDry heat
Striker 3
AGEs Regulate Oxidant Stress
Diet is a major source of excess oxidants (AGEs).
Koschinsky, T., Vlassara et al. PNAS 1997
ROS, AGEs, NOS E.R. Stress
Inflammation, Proliferation, Apoptosis or Cell Death
NAPDH ox, PKC, Mitochondrial Oxidant
Stress etc.Glucose, Fatty
Acids
Exogenous Oxidants (AGEs)
Food Intake
ROS
What is the Source of AGEs?
Oxidant (AGEs) Content ofCommon Foods
This is not “starvation”, it is French cooking!!
17MASHED1522Potato: fried
502SUSHI1348Salmon: broiled
1011STEWED5245Chicken: broiled
2000STEWED5367Beef: broiled
Low AGE diet (U/mg)Regular diet (U/mg)
AGE Formation Depends on Temperature of Cooking
A 50% Reduction may be sufficient clinically.
What is the effect of restriction of AGEs in diet?
Striker et al.88
Diabetic Subjects: AGE-Restricted Diet (x 4-6 wks)Reduces Inflammatory Markers
-20
-10
0
10
**-50
-25
0
25
50
*
hsCRP TNF α VCAM -1
%
fro
m b
asel
ine
-50
0
50
100
**
H.Vlassara, Proc.Nat.Acad.Sc: ‘O2
Type 2 Diabetes Trial: AGE Restriction and Insulin Resistance (x4 mos)
AGE-Restriction Reduces Plasma Insulin and Leptin
Vlassara group: Db Care, 2011
Plasma Insulin (μU/ml)
0
5
10
15
20
25
Pre- Post-
*
Leptin (ng/ml)
0
10
20
30
40
*
Pre- Post-
Type 2 Diabetes Trial: AGE Restriction (4 mo)
Vlassara group: Db Care, 2011
AGER1
0
50
100
150
200
250
pre post
*
NL
ADIPONECTIN
0
2
4
6
8
10
12 *
pre post NL
SIRT-1
0
100
200
300
400
500 *
pre post NL
AGE-Restriction Normalizes anti-oxidant defenses in T2D: i.e. AGER1, SIRT-1 and Adiponectin
Renal Function and AGEs
• The kidneys are a primary site for metabolism and excretion of oxidants
• Decreased renal function: increased OS and inflammation (TNFα) due to reduced anti-oxidant defenses
Striker et al.
Uribarri, J, Vlassara , H, JAGS, 2009
• AGEs and Renal Function are Linked
• Oral AGEs Influence Systemic AGEs at All Levels of Renal Function
Renal Function and Serum AGEs
(years)
0
50
100
20 40 60 80 100
150
200r = - 0.447p = 0.0001
eGFRCr vs. Aging (years) eGFRCr vs. Serum CML
0
10
20
eGFRCr
0 50 100 150 200
r = - 0.647p = 0.0001
30
40
50
60
NORMAL :
sAGE
(u/m
l)
0
1015202530
hours0 20 40
5
High AGE Low AGE
Serum60
30
0 20 40hours
Urine
Serum/Urine AGEs in Diabetes after Meals
GFR= 84, proteinuria GFR= 100, μ/alb
hours
0
60
30
20 40
DIABETIC
0
202530
0 20 40
5
hours
10sAGE
(u/m
l)
15
AGE excretion can be reduced prior to clinically significant changes in GFRT. Koshinsky. H.Vlassara PNAS 1997
14
Urine CML (nmoles/24 hr)
0.0
4,000.0
8,000.0
12,000.0
16,000.0
20,000.0
1st 5th visit
*p<0.05
AGE Restriction Restores Urinary Excretion of AGEs (active and filtration)
Vlassara group, 2009
AGE-Restriction Effect on Oxidant Excretion (MG) and/or filtration (CML) in T2D
This also applies to Normal Adults!!
Urine MG (nmoles/24 hr)
0.00
100.00
200.00
300.00
400.00
1
* p<0.025
5th visit
T2 Diabetic Nephropathy and AGE restriction (4 mo)
Vlassara et al: PNAS 2002; JCEM, 2009; Diab Care 2-12
% Change-100 -50 0 50 100
RAGE
8-iso
sCML
TNFα
VCAM-1
sMG
AGER1
AGE-Restricted Diet Restores Anti-ox (AGER1) Levels, Promotes Renal Elimination of AGEs, and Reduces OS/Inflammation (i.e.TNFα)
Lowering oxidant intake allows kidneys to excrete AGEs, which reduces OS and Inflammation.
Standard Diet AGE-Restricted
AGE-Restricted Diet Prevents Diabetic Nephropathy in NOD Mice
Restriction of AGEs – not nutrients or blood glucose – can Prevent CKD in T1D-Susceptible Mice
Peppa, M.: Diabetes J., 2005
Ways to Decrease AGE Uptake
• Change AGEs in food– Western diet is rich in AGEs and NOT EVERYONE
CAN FOLLOW THE DIET• Sequester AGEs in the gut and eliminate them
in the stool– Sevelamer is a non-absorbable polymer that was
found to reduce HbA1c and lipids, similar to effects seen in patients treated with a low-oxidant diet. This suggested it might remove AGEs
20
40
60
80
100 *
AGE AGE +pH=1
AGE +pH=7.0
%
Bou
nd 1
25 I-
AGE-
BSA
0
Sevelamer
Binding of AGEs in vitro:Sevelamer Sequesters AGEs in a pH-dependent manner
1) Sevelamer carbonate treatment would result in a 20% decrease in serum AGEs within 8 weeks.
Therefore we proposed a Pilot Cross-over Study in 20 T2D patients with CKD Stages 2-4 with the following Hypotheses:
2) Renvela treatment would decrease serum inflam/ROS markers by 10% within 8 weeks.
No Medications were changed, all participants were on drugs to control BP, many were on statins, insulin, etc..
Vlassara group, CJASN, 2011
% Change
25
0
-50
TNFα
-25
8-iso
sCM
L
TNFα
sMG
*
8-iso
sCM
L
sMG
***
50
CaC03 (CONTROL)
-75
-100
75
100
AGER
1SI
RT1
*
*
FGF2
3
*
AGER
1SI
RT1
SEVELAMER
SEVELAMER Lowers OS and Inflammation and Restores AGER1, SIRT1 and FGF23 mRNA in T2D with CKD
METABOLIC CHANGES: Sevelamer Carbonate Lowers HbA1c and Plasma Lipids in T2D with CKD
Vlassara group, CJASN, 2011
LDL-
Chol
10
0
-20
Tota
l Cho
l
-10
HbA1
c
Trig
**
*
20
CaC03 SEVELAMER
Tota
l Cho
lLD
L-Ch
ol
HbA1
cTr
ig
*
% C
hang
e
Striker et al. 22
Conclusions Pilot Trial• Sevelamer lowered serum (and cellular) AGE
levels, by sequestering AGEs in the gut• Sevelamer lowered markers of Oxidative Stress
and inflammation and decreased FGF23• Sevelamer lowered HgbA1c, and lipids (t-chol,
triglycerides, even though most were on statins)
• These data suggest that Sevelamer reduces AGEs as one primary target
• A longer/larger study is now being conducted to validate these results
Striker et al.
Proposed New Study of Sevelamer: Examine the Effects of Sevelamer Carbonate on
Cardio-Metabolic Risk Factors and Selected Aspects of Kidney Function in Type 2 Diabetics
with Stage 2-4 CKD
Hypothesis: Sevelamer carbonate (Renvela) will lower inflammation and oxidative stress in the body by absorbing AGEs in the gut and removing them from the body.
Study Design• 6 month prospective, comparative study• 120 patients randomized to receive, in parallel, either:
1. Sevelamer carbonate (1600 mg tid) 2. Calcium carbonate (1200 mg tid)
• Endpoints• Primary: HbA1c and AGEs• Secondary: markers of glucose metabolism,
inflammation, oxidative stress
Dietary AGE content is assessed
Recruitment
• MSSM: • 89 randomized
• Beth Israel: • 49 randomized
• Sponsor: Genzyme-Sanofi• Industry sponsored (investigator-initiated)
Striker et al.
Summary• AGEs elevate levels of inflammatory markers and oxidative stress• The diet is a major source of oxidants (AGEs) in DM.• The kidneys are the major sites of disposal of oxidants, (and
AGEs), so treatment/prevention of CKD is critical• Major internal and external sources of ROS/Infl and AGEs can be
managed with current medications
• Sevelamer reduce oxidants (AGEs) and improves anti-oxidants, lipids, FGF23 and glucose control in T2D
Many Thanks to Team AGE
MSSM• Gary Striker• Helen Vlassara• Nephrology: Jaime Uribarri,
John He, Shirisha Guthikonda
• Endocrinology: Ronald Tamler
Beth Israel New York• Endocrinology: Leonid
Poretsky, Augustin Busta, Carla Romero, Yun Feng
• Nephrology: Nikolai Harbord
STUDY COORDINATORS AND MANY OTHER COLLABORATTORS…………