Anthony Rosenzweig, MD

Cardiovascular Institute

Beth Israel Deaconess Medical Center

arosenzw@bidmc.harvard.edu

AHA BCVS

July 22, 2010

Diet, Vascular Disease, and Progenitor Cells

Diet and atherosclerosis in ApoE-/- mice

Effects of a LCHP Diet in Mice

Weight Gain

Atherosclerosis in mice is increased on LCHP Diet

Effects of a LCHP Diet in Mice

Cholesterol oxLDL 8-oxoguanine

Serum Concentration SC WD LCHP

Total cholesterol (mg/dL) 358.7 ± 28.3 1470 ± 170.7 1408 ± 251.2

High-density lipoprotein (mg/dL) 190.7 ± 6.1 861 ± 146.9 756 ± 121.1

Triglycerides (mg/dL) 108.0 ± 6.9 95 ± 27.8 155 ± 60.7

Glucose (fasting; mg/dL) 136 ± 6.9 185 ± 20.5 142 ± 17.7

Glucose (non-fasting; mg/dL) NA 406.9 ± 58.9 274.2 ± 51.0

Insulin (ng/ml) 307.5 ± 322.2 432.9 ± 477.9 308.5 ± 205.4

Effects of a LCHP Diet in Mice

Inflammation is not increased on LCHP Diet

Why is Atherogenesis Increased on LCHP diet?

Increased atherosclerosis not accounted for by:

• Serum lipids, insulin, or glucose

• Systemic or vascular inflammation

• Oxidative stress

“The great tragedy of Science: the slaying of a

beautiful hypothesis by an ugly fact”

-- Thomas Henry Huxley

Is there a counter-balance to vascular injury?

Vascular Progenitor Cell

Endothelial CellPericyte

InjuryRepair

Vascular (Endothelial) Progenitor Cells

• Present in bone-marrow and peripheral blood

• Peripheral levels decrease with:

• Diabetes

• Smoking

• Hypercholesterolemia

• Coronary disease

• Peripheral levels increase with:

• Exercise

• Statin treatment

• Correlate with better vascular function

NEJM 2003

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SC WD LCHP SC WD LCHP

*#

ApoE +/+ApoE -/-

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Bone marrow EPCs are Decreased on LCHP diet

SC WD LCHP

Sca1-F

ITC

Flk1-PE

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SC WD LCHP

Circulating EPCs are Decreased on LCHP Diet

p-Akt is decreased by LCHP diets in EPCs

p-Akt in lin-, Flk-1+ cells

Murine Hindlimb Ischemia Model

Niiyama H, Huang NF, Rollins MD, Cooke JP (2009).JoVE. 23. http://www.jove.com

LCHP

WD

Neovascularization in a hindlimb ischemia model (WT)

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LCHP

Ischemia-induced Neovascularization is Impaired on LCHP Diet

Working Hypothesis: Balance Between Injury and Repair

Vascular Progenitor Cell

Pericyte

Injur

y

Repair

SC WD LCHP

Injury Repair

Endothelial Cell

The Problem: What‟s a Vascular Progenitor Cell?

Vascular Progenitor Cell

PericyteEndothelial Cell

Humans:

• CD34

• CD133

• KDR (VEGFR)

• Mature markers absent

• Endothelial Colony formation

•Ac-LDL, Lectin binding

Mice:

• Sca-1

• Flk1

• Mature markers absent

• Endothelial Colony formationEndothelial Colony Matrigel Tube

Formation

Phage Display for Novel VPC Markers

4 cycles of positive

selection

Positive Selection:

Lineage-negative, Flk-1-

positive BMCs

Negative selection:

Lineage-negative, Flk-1-

negative BMCs

6 „hits‟Ralph Weissleder

Kimberly Kelly

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No

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f C

FU

s (

av

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1x10

6cells)

CFU-EPC assay +/- phage+ cells

Control + Phage

Control

P46

P46-positive Cells Enhance Endothelial Colony and Tube-Formation

Tube Formation in vitro

In Vivo Staining of Endogenous Neovasculature with Phage

Tie2-GFP CD31-Rhodamine DAPI

Ischemic

Limb

Control

Limb

Adoptive Transfer of P46-Positive Bone Marrow from

Tie2-GFP mice into Hind-Limb Ischemia Model

Summary

• Dietary macronutrients (other than fat) can modulate

atherogenesis and neovascularization without altering

vascular inflammation in mice.

• These studies do not distinguish between the effects of low

carbohydrate and those of high protein in the diet.

• Vascular pathology may reflect a balance between injury

and repair.

• The role vascular progenitors warrants further evaluation in

animal models and people, but will likely require more

specific markers of

Collaborators

Rosenzweig LabShi Yin Foo

Dorota Sadowicz

Matt Coggins

Saumya Das

BIDMC Cath Lab

Joanna Wyrkrykowska

Riya Chacko

Mike Rosenberg

MGH

Ralph Weissleder

Kimberly Kelly

Robert E. Gerszten

Eric Heller

Kathryn J. Moore

Jennifer J. Manning-Tobin

Center for Life Sciences

Cardiac

Diabetes

Network

National Heart

Lung and Blood Institute

People Science Health