The benefits of MiECC on the human endothelium · VEGFR3 signalling select 'tip cells' (TCs) for sprouting. •TC sprouting behaviour is facilitated by the vascular endothelial cadherin-mediated

The benefits of MiECC on the human endothelium

Dr. Winkler Bernhard

Consultant Cardiac Surgery

Department of Cardiac Surgery

University Hospital Berne

Universitätsklinik für Herz- und Gefässchirurgie

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• activation of blood elements

• vasoactive substances und endotoxines

• body fluid balance, hemodilution

• activation of coagulation

• embolisation and thrombus formation

• adsorption of serum proteins

Influence on the endothelium: direct vs indirect

Negative effects of cardio pulmonary

bypass (CPB) or standard

extracorporeal circulation (ECC)

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• contact system

CPB: Activation of blood elements

Edmunds HL. Inflammatory Response to CPB. Ann Thorac Surg 1998;66:S12-6

Systemic

proinflammatory

response

coagulation

disorder

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• complement system• activated by classical pathway via F XIIa, alternative pathway

activated by C3b;

• C5a directly activates Nc, leads to cell lysis

• C3a negative effect on myocardial contractility

• C3a, 4a, 5a increase capillary permeability, release of Histamin:

vasodilation, bronchospasm


main proinflammatory stimulus

associated with creation of free

oxygen radicals and significant

morbidity [1][1] Edmunds LH Jr. Why CPB makes patients sick, in Karp RB et al. (eds): Advances in

Cardiac Surgery, Baltimore, Mosby-Year Book, Inc 1995:131-67

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• Platelets

• activated by Thrombin, Adrenalin, plateled activating factor

– release of inflammatory mediators

• Serotonin, TXA2, Hydrolase, Proteinase

– activation of coagulation

– depletion by adsorption, aggregation, dilution


Increased capillary

permeability, vasomotor tone,

Nc attraction

Increased bleeding risk

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• Monocytes

– release IL-8, IL-6 und IL-1 during and after CPB

• Endothelial cells

– release t-PA, Prostacyclin, Endothelin 1 and PAF

– activate fibrinolysis and platelets


systemic proinflammatory response

vasoconstriction, coagulation disorders

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Function of the Endothelium

Barrier function:

the endothelium acts as a semi-selective barrier, controlling transit of

cells into and out of the bloodstream

Excessive or prolonged increases in permeability of the endothelial

monolayer, as in cases of chronic inflammation, may lead to tissue

edema.

Thrombosis and fibrinolisis:

The endothelium normally provides a non-thrombogenic surface

because it contains, for example, heparan sulfate which acts as cofactor

for activating antithrombin (a protease that inactivates several factors in

the coagulation cascade)

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The Endothelium-nearly an organ

Vascoconstriction and Vasodilatation, and hence the control

of blood pressure

Repair of damaged or diseased organs via an injection of

blood vessel cells

Angiopioetin-2 secretion: works with VEGF to facilitate cell

proliferation and migration of endothelial cells

Formation of new blood vessels- Angiogenesis

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Stimuli

• In the absence of pro-angiogenic stimuli, endothelial cells (ECs) are

retained in a quiescent state.

• In addition, EC homeostasis is maintained by low-level autocrine

vascular endothelial growth factor A (VEGFA) signalling124.

• During angiogenesis, high levels of exogenous pro-angiogenic factors

(such as VEGFA and VEGFC) and of VEGF receptor 2 (VEGFR2) or

VEGFR3 signalling select 'tip cells' (TCs) for sprouting.

• TC sprouting behaviour is facilitated by the vascular endothelial

cadherin-mediated loosening of EC–EC junctions, matrix

metalloproteinase-mediated degradation of extracellular matrix (ECM)

and the detachment of pericytes .

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Endothelial repair: CEC, EPC- adventitial stem cells

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Endothelial Progenitors

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CEC, EPC,EC,SMC…?

• Detachment of endothelial cells may represent serious

injury of the endothelium after cardiopulmonary bypass.

• In diabetic patients, smokers,after myocardial infarction the

number of CEC ( circulation endothelial cells) can be used

as a measure to quantify and detect the grade of vascular

injury/damage

• Difference between conventional or minimized circuit ?

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How to study CEC

Circulating endothelial cells can be isolated from peripheral blood

samples at specific time points:

• Sample I: preoperatively before onset of CPB to acquire

baseline cell number

• Sample II: 30 minutes after initiation of CPB

• Sample III: 12 hours postoperatively

• Sample IV: 24 hours postoperatively

• Sample V: 48h after CPB initiation

• Sample VI: 72 after CPB

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CEC detection

• Parameters:

–von Willebrand Factor (vWF)

–Soluble Thrombomodulin (sTM)

–Circulating Endothelial Cell (CEC): magnetic beads,

sorting, FACS

–Progenitor/ EC detection:/ FACS

–CD 34

–CD 309

–CD 31 bright cells

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Possible Solutions through using a MIECC

• Minimized Cardiopulmonary Bypass Circuit / Priming

• Rotary Pump / Hydrophobe mini-Oxygenator

• Cristalloide Single-Shot Cardioplegia: Cardioplexol®

• Reduction of blood-air interface: Cardiosmart®

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Literature I

The endothelial damage, the granulocyte sequestration, and

its activation are much lower since the artificial surface is

smaller *

*P. Massoudy et al.

Reduction of pro-inflammatory cytokine levels and

cellular adhesion in CABG procedures with separated

pulmonary and systemic extracorporeal circulation

without an oxygenator Eur J Cardiothorac Surg, 2000, pp.

729–736

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Literature II

• Quantification of circulating endothelial cells and perioperative

outcome in less invasive coronary surgery: Are Off-pump

procedures superior than minimized extracorporeal circulation?

• Conceptional advantages of closed-minimised-CPB-systems

(ROCsafe™) result in morbidity and mortality comparable with OPCAB

procedures. MiniHLM therefore minimizes CPB-related systemic and

organ injury as demonstrated by low CEC-values which indicates intact

endothelial integrity.

*T. Witwer et al. Thorac cardiovasc Surg 2014; 62 - OP4

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Skrabal, A. Liebold et al JVCTS 2006

• 20 patients , elective coronary bypass grafting were randomly assigned to

either the minimal extracorporeal circulation system or the standard

cardiopulmonary bypass circuit

• Ten healthy volunteers served as controls.

• Circulating endothelial cells per milliliter of full blood were perioperatively

determined by immunomagnetic cell separation technique. Endothelial plasma

markers were measured by enzyme-linked immunosorbent assay.

Preoperative circulating endothelial cell numbers did not differ between the

experimental groups, but were significantly higher than in the healthy controls

(18.6 ± 5.6 vs 7.2 ± 3.8, P < .001) ( cardiovascular risk factors..)

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Skrabal, A. Liebold et al JVCTS 2006

• At 6 hours, circulating endothelial cell numbers increased significantly

compared with baseline in both experimental groups and peaked at 12 hours

after cardiopulmonary bypass initiation, each time with significantly lower

values in the minimal extracorporeal circulation group (6 hours: 44.0 ± 9.9 vs

29.6 ± 9.8, P = .007; 12 hours: 48.1 ± 6.8 vs 31.8 ± 7.1, P < .001)

• Likewise, von Willebrand factor and soluble thrombomodulin postoperatively

increased in both groups with a tendency toward lower levels in the minimal

extracorporeal circulation group.

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Conclusions

CECs are more accurate in detecting the intrinsic

endothelial damage.

Patients with cardiovascular disease not only have

a higher CEC baseline ( more damage-more

renewal); additional damage is caused by the

standard CPB

The MiECC system may be less injurious to

endothelium than the standard CPB.

Call for large study??


THANK YOU for your attention

Documents

The benefits of MiECC on the human endothelium · VEGFR3 signalling select 'tip cells' (TCs) for sprouting. •TC sprouting behaviour is facilitated by the vascular endothelial cadherin-mediated