Jie Cui, MD, MScNephrology Division

Cardiovascular Research CenterMassachuestts General Hospital

ASDIN 02/2017

Statin therapy Decreases Vascular Inflammation andProlongs Patency in Murine Arteriovenous Fistula

Background

• The primary failure rate of AVF isaround 50%.

• The patency after percutaneousangioplasty is not satisfactory. Nomedical therapies proven.

• Annual cost of vascular accessmaintenance is around $2 billion inthe U.S.A the U.S

AVF

AVG

Background

Background

Inflammation plays a role in neointimal hyperplasia and thrombosis

• Patients with unsuccessful AVF have higher CRP and fibrinogen level.1

• Thromboses AVFs have more macrophages and lymphocytes compared to nonthrombosed fistulas. 2

• The patency and luminal area/total cross-sectional area were all higher in MCP1-/-micecompared to MCP1+/+ mice.3

1. Kaygin MA et al. The relationship between arteriovenous fistulae success and inflammation. Ten Fail 2013 Sep; 35(8): 1085-8

2. Chi-Jen Chang et al. Thromboses arteriovenous fistula for hemodialysis access is characterized by a marked inflammatory activity. KI, vol 68(2005), 1312-1314

3. Julio P.Juncos et al. MCP-1 contributes to arteriovenous fistula failure. JASN. 2011 Jan; 22(1): 43-48

Factors that predict AVF maturation

Hemodynamic changes of vessel diameter and blood flow

2 weeks:634-750 ml/min1

4 weeks: diameter 0.45cm, blood flow 700ml/min 2

12 weeks: diameter 0.47cm, blood flow 675ml/min

If blood flow rate >500ml/min at 6 to 8 weeks, 70% of AVF is usable for hemodialysis

1 Lin SL. et al. Effects of age and diabetes on blood flow rate andprimary outcome of newly created hemodialysis arteriovenous fistula. Am J Nephrol 18: 96-100, 19982 Robbin ML et al. Hemodialysis arteriovenous fistula maturity: US evaluation. Radiology 255;59-64,2002

Clinical Significances

• New imaging approaches to predict AVF failure could betteridentify high risk AVF failure patients for novel AVF therapies.

• New therapies to improve AVF patency could markedly improveESRD patients’ survival and health care expenditure

• Establish clinical relevant murine AVF model to investigateinflammation and thrombotic mechanisms of AVF failure invivo

• Develop molecular imaging approaches to predict AVFfailure

• Evaluate anti-inflammatory agent to prolong AVF patency

Aims

AVF model

• New AVF model: end to sideinternal jugular vein-carotidartery anastomosis

• Evaluate venous stenosis andthrombus formation

• Evaluate blood flow changes Venous outflow

Figure. Trends of blood flow in the venous outflow after arteriovenous fistula creation.A. The mean blood flow measured by Transonic flow probe immediately post-surgerywas 1.24±0.47 ml/min. The blood flow decreased on day 7 (1.05±0.71 ml/min), day 14(0.47±0.51ml/min) and day 21 (0.19±0.23 ml/min). B. The blood flow in the fistula onday 14 was correlated with day 7 blood flow (r=0.80, p=0.02).

AB

Blood Flow Changes

Distribution of inflammatory cells

D7

D14

CD68 F4/80 NIMP

*

*

Structure

Distribution

Cross-linked iron oxide:stable under harshconditions (do notchange in size, bloodhalf-life, or loss of itsdextran coat)

Cross-linked iron oxide (CLIO)

CLIO-VT680 CD68 CLIO-VT680

CD68

Day 1AVF

surgery

Day 6CLIO-VT680

injection

Day 14Sac

Day 7Imaging

250μm

250μm 250μm

250μm 250μm

250μm 250μm

Figure: In vivo epifluorescence imaging of arteriovenous fistula outflow using CLIO-VT680. A. CLIO-VT680 was injected on day 6 post-AVF creation (10mg/kg). A. In vivo epiflorescence imaging wasperformed 24 hours later. B. The mean signal intensity of venous outflow in AVF side was muchhigher than the control vein (p<0.0001)

FITC

CLIO

FITCCLIO

A

B C

p<0.001

Study Protocol

B

Figure. The blood flow changes from day 7 to Day 14 was correlated with day 7 CLIO-VT680target to back ground ratio (p=0.02, r=-0.57). B. If day 7 TBR<4, the average changes of bloodflow from day 7 to day 14 was 0.09±0.21 ml/min). If day 7 TBR>4, the average changes of bloodflow from day 7 to day 14 was -0.8±0.27 ml/min), p=0.02.

A B

p=0.02r=-0.57

p=0.02

Blood flow changes correlates with CLIO-VT680 TBR

Statin

• Statin— anti-inflammatory pleiotropic properties• Animal study: decrease neointimal hyperplasia1

• Human study: Controversial2,3,4

• Higher dose may be required to achieve the clinical effects

1. Yamanouchi D. et al. Hydrophilic statin suppresses vein graft intimal hyperplasia via endothelial cell-tropic Rho-kinase inhibition. J Vasc Surg. 2005 Oct; 42(4):757-642. Roberto Pisoni et al. Statin therapy is not associated with improved vascular access outcomes. CJASN Aug 2010. vol 5. no. 8 1447-1450;3. Righetti M et al. Some old drugs improve late primary patency rate of native arteriovenous fistulas in hemodialysis patients. Ann Vasc Surg 23: 491-497, 204. Martinez L et al. Distinct Impact of three different statins on arteriovenous fistula outcomes: a retrospective analysis. JVA 2016 Nov 2; 17(6): 471-476

p=0.03

Day 1AVF

surgery

Day 14Sac

Day -7Atorvastatin1.14mg/kg

Study Protocol

Figure. The volume of neointimal hyperplasia was comparable in PBS treated mice and statin treatedmice in both day 7 and day 14 (p>0.05).

Day 7Sac

Figure. In mice treated with PBC, the meanblood flow changes from day 7 to day 14was -0.8±0.32 ml/min. However, in micetreated with statin, the mean blood flowchanges is 0.14±0.18 (p=0.02).

Blood flow changes in Statin vs PBS

p=0.02

p=0.02

Figure. The primary patency of AVF in micetreated with statin was much higher than

Statin increases venous outflow area

Figure. The venous outflow area was bigger in statin treated mice compared to PBS treated mice.

p=0.03

Figure. The CLIO-VT680 target to background ratio of venous outflow/control vein inPBS and statin treated mice on day 7. A. CLIO-VT680 target to background ratio washigher in PBS treated group compared to statin treated group (p=0.03). B. TBR wasmeasured every 120um from the anastomosis to the distal of the venous outflow,which showed PBS treated group had higher CLIO-VT680 signals compared to statintreated group.

Statin decreased adventitial inflammatory response

p=0.03

Day 1AVF

surgery

Day 6CLIO-VT680

injection

Day 14Sac

Day 7Imaging

Day -7Atorvastatin1.14mg/kg

FITC

CLIO

FITCCLIO

Platelet activities and Fibrinogenesis

Figure. Platelet activities and fibrinogenesis were comparable in statin treated andPBS treated group.

1.Inflammatory response in adventitium post-AVF can beimaged in vivo.

2.The inflammatory response on day 7 correlated withblood flow changes from day 7 to day 14.

3.Statin can decrease inflammatory response andprolonged AVF patency in murine animal model

Conclusions

AcknowledgementsMGH CSB

Jason R. McCarthy, PhDCharles P. Lin, PhD

Matthias Nahrendorf, PhDRalph Weissleder, MD

MGH Nephrology

Amin Arnaout, MDRavi Thadhani, MD

MGH CVRC/Cardiology

Farouc Jaffer, MD, PhDChase Kessinger, PhD

Harkamal Jhajj, BSAdam Mauskapf, BS

Victor Guanming Qi, MD, PhD

BWH Cardiology

Peter Libby, MD

BWH Nephrology

Joseph Bonventre, MD, PhD

Funding

American Society of Nephrology Ben. J Lipps Research Fellowship GrantAmerican Society of Diagnostic and Interventional Nephrology Fellowship Grantt