Cyclosporine A reduces microvascular obstruction and preserves left ventricular function deterioration following myocardial ischemia and reperfusion

Abstract

Postconditioning and cyclosporine A prevent mitochondrial permeability transition pore opening providing cardioprotection during ischemia/reperfusion. Whether microvascular obstruction is affected by these interventions is largely unknown. Pigs subjected to coronary occlusion for 1 h followed by 3 h of reperfusion were assigned to control (n = 8), postconditioning (n = 9) or cyclosporine A intravenous infusion 10-15 min before the end of ischemia (n = 8). Postconditioning was induced by 8 cycles of repeated 30-s balloon inflation and deflation. After 3 h of reperfusion magnetic resonance imaging, triphenyltetrazolium chloride/Evans blue staining and histopathology were performed. Microvascular obstruction (MVO, percentage of gadolinium-hyperenhanced area) was measured early (3 min) and late (12 min) after contrast injection. Infarct size with double staining was smaller in cyclosporine (46.2 ± 3.1%, P = 0.016) and postconditioning pigs (47.6 ± 3.9%, P = 0.008) versus controls (53.8 ± 4.1%). Late MVO was significantly reduced by cyclosporine (13.9 ± 9.6%, P = 0.047) but not postconditioning (23.6 ± 11.7%, P = 0.66) when compared with controls (32.0 ± 16.9%). Myocardial blood flow in the late MVO was improved with cyclosporine versus controls (0.30 ± 0.06 vs 0.21 ± 0.03 ml/g/min, P = 0.002) and was inversely correlated with late-MVO extent (R(2) = 0.93, P < 0.0001). Deterioration of left ventricular ejection fraction (LVEF) between baseline and 3 h of reperfusion was smaller with cyclosporine (-7.9 ± 2.4%, P = 0.008) but not postconditioning (-12.0 ± 5.5%, P = 0.22) when compared with controls (-16.4 ± 5.5%). In the three groups, infarct size (β = -0.69, P < 0.001) and late MVO (β = -0.33, P = 0.02) were independent predictors of LVEF deterioration following ischemia/reperfusion (R(2) = 0.73, P < 0.001). Despite both cyclosporine A and postconditioning reduce infarct size, only cyclosporine A infusion had a beneficial effect on microvascular damage and was associated with better preserved LV function when compared with controls.

Figures

Fig. 1

Methods. a Study protocol. b Gadolinium-enhanced (GE) images in short and horizontal long axis. The microvascular obstruction (indicated by arrows) is a dark zone in the high-intensity signal of infarct area. The left ventricle landmarks—place of insertion of papillary muscles (asterisk) and right ventricle (♥)—have been used to obtain biopsy specimens from the triphenyltetrazolium (TTC)-determined infarct territory. c Representative pictures of TTC/Evans blue staining with indicated place of biopsy corresponding with gadolinium-enhanced area of infarct and microvascular obstruction. d Microscopic pictures of infarct region with and without erythrocytes stasis. Black arrows indicate interstitial edema whereas white arrows show capillaries occupied by erythrocytes

Fig. 2

Cardiovascular magnetic resonance imaging and histopathology. Representative pictures of corresponding: a T2-weighted myocardial edema, b hyperenhanced area of infarct with dark zone of microvascular obstruction (MVO), c two perfusion slices of first pass with contrast medium in the right ventricle (i), in both ventricles and myocardium (ii) and in the left ventricle (iii), d no-reflow region as a lack of thioflavin S staining, e the infarct region determined by triphenyltetrazolium staining. *MVO region, **gadolinium-enhanced infarct area without MVO, ***border zone, ****remote myocardium

Fig. 3

The area at risk and infarct size. Area at risk (AAR) by Evans blue and infarct size by triphenyltetrazolium staining, box plot shows median and interquartile range (IQR, Q3–Q1). Q1 and Q3 are the first and third quartiles. Whiskers are drawn at minimum and maximum. LV left ventricle, Con control group, PoC postconditioning group, CsA cyclosporine group, *versus controls

Fig. 4

Microvascular obstruction and its dynamics. Gadolinium-enhanced (GE) images in short (S) and horizontal long (L) axis obtained at 3 (early) and 12 (late) min post-contrast. a Representative pictures of control pig with a small change of microvascular obstruction (MVO, indicated by arrows) extent by 25 % between 3 and 12 min (infarct size of 27 % of left ventricle). b Representative pictures of pig pre-treated with cyclosporine A with substantial decrease of MVO area by 60 % (infarct size of 25 % of left ventricle). c The early MVO and late MVO. Scatter plot shows absolute values and means. d The reduction of MVO area between 3 and 12 min post-contrast, e the late-to-early MVO ratio. Box plot shows median and interquartile range (IQR, Q3–Q1). Q1 and Q3 are the first and third quartiles. Whiskers are drawn at minimum and maximum, Con control group, PoC postconditioning group, CsA cyclosporine group. *versus controls

Fig. 5

Changes of left ventricular ejection fraction and its determinants. a Changes of left ventricular ejection fraction between baseline and 3 h of reperfusion (LVEF). Box plot shows median and interquartile range (IQR, Q3–Q1). Q1 and Q3 are the first and third quartiles. Whiskers are drawn at minimum and maximum, Con control group, PoC postconditioning group, CsA cyclosporine A group, *versus controls. The relationship between: b LVEF and microvascular obstruction 12 min post-contrast (late MVO) or c LVEF and infarct size as percentage of area at risk (AAR) as measured by double staining

Fig. 6

Myocardial blood flow. a Myocardial blood flow (MBF) in the territory of late microvascular obstruction (MVO), gadolinium-hyperenhanced area without MVO, border zone and in the remote myocardium. The relationship between b MBF in the region of late MVO and its size and c MBF in hyperenhanced area without MVO and the size of gadolinium-enhanced area of infarct. Con control group, CsA cyclosporine group

Fig. 7

No-reflow area. a No-reflow area as measured by the lack of thioflavin S staining within infarct size (IS) as measured by triphenyltetrazolium staining. The relationship between no-reflow area and b microvascular obstruction (MVO) or c late-to-early MVO ratio and d the relationship between late-to-early MVO ratio and myocardial blood flow in the late MVO

Fig. 8

Histological composition of infarct area with and without microvascular obstruction. Data are shown as mean and absolute values