Release of active peptidylarginine deiminase into the circulation during acute inflammation induced by coronary artery bypass surgery

Figures & data

Table 1 Patient characteristics

		Non-smokers n=20	Smokers n=16
Preoperative characteristics
Male/female	n	19/1	13/3
Age, years	Mean (range)	67.6 (47–82)	66.3 (37–80)
BMI, kg/m^2	Mean±SD	28.4±3.2	26.6±4.8
Medical and surgical history
Hypertension	n (%)	15 (75)	11 (52.4)
Hypercholesterolemia	n (%)	15 (75)	11 (52.4)
Myocardial infarct	n (%)	7 (35)	5 (23.8)
Previous PCI	n (%)	5 (25)	3 (14.3)
T2DM	n (%)	8 (40)	5 (23.8)
COPD	n (%)	1 (5)	3 (14.3)
LVEF
<40%	n (%)	2 (10)	1 (6.25)
40–55%	n (%)	8 (40)	11 (68.8)
>55%	n (%)	10 (50)	4 (25.0)
SpO2, %	Mean±SD	98.2±1.3	98.3±1.3
Perioperative characteristics
CPB time, min	Mean±SD	77.8±17.8	818±25.8
Aortic cross-clamp time, min	Mean±SD	46±13.3	46.9±15.3
No. of grafts	Median (range)	2 (1–2)	2 (1–3)

Abbreviations: BMI, body mass index; PCI, percutaneous coronary intervention; LVEF, left ventricular ejection fraction; SpO₂, peripheral capillary oxygen saturation; CPB, cardiopulmonary bypass.

Figure 1 Circulating PAD2 and PAD4 levels before and after CABG surgery. Circulating levels of PAD2 and PAD4 were assessed in 16 smokers and 20 non-smokers before and after CABG surgery. (A) Serum PAD2 concentration before surgery. (B) Serum PAD2 concentration after surgery. (C) Serum PAD2 concentration of all patients before and after CABG. (D) Serum PAD4 concentration before surgery. (E) Serum PAD4 concentration after surgery. (F) Serum PAD4 concentration of all patients before and after CABG. Levels below the lower limit of detection of the two tests (100 pg/mL) were set to 100 pg/mL. ****p<0.0001.

Abbreviations: ns, not significant; PAD, peptidylarginine deiminase; CABG, coronary artery bypass grafting.

Figure 2 PAD activity in serum after CABG surgery. ELISA microtiter plates coated with human fibrinogen were incubated for 4 hrs with sera from 36 patients who had undergone CABG surgery, either with 1 mM DTT (+DTT) or without additives (no DTT). As negative control, each serum was tested in the presence of 25 mM EDTA. (A) PAD activity in serum among smokers and non-smokers before surgery. (B) PAD activity in serum of smokers and non-smokers after surgery. (C) PAD activity at baseline in serum containing 1 mM DTT. (D) PAD activity of all untreated serum samples before and after surgery. Citrullination was measured using anti-citrullinated fibrinogen mAb (20B2) recognizing a citrullinated epitope in fibrinogen. Data are expressed as average OD of duplicate measurements after subtraction of the negative controls, and median and interquartile ranges of the dataset are shown. ***p<0.001, ****p<0.0001.

Abbreviations: PAD, peptidylarginine deiminase; CABG, coronary artery bypass grafting; DTT, dithiothreitol.

Figure 3 Circulating levels of cytokines and markers of neutrophil degranulation before and after CABG. Serum levels of (A) IL-6, (B) IL-10, (C) CXCL-8, (D) MPO, (E) lipocalin-2, and (F) MMP-9 before and after surgery. ****p<0.0001.

Abbreviations: CABG, coronary artery bypass grafting; MPO, myeloperoxidase; MMP, matrix metallopeptidase.

Table 2 Association between PAD2 levels and inflammatory markers in serum

	IL-6	IL-10	CXCL-8	MPO	MMP-9	Lipocalin-2
Before	rs=−0.12 p=0.49	rs=−0.04 p=0.84	rs=−0.08 p=0.64	rs=0.024 p=0.88	rs=−0.01 p=0.97	rs=0.014 p=0.93
After	rs=0.09 p=0.56	rs=−0.014 p=0.93	rs=0.19 p=0.25	rs=0.36, p=0.03	rs=0.32 p=0.056	rs=0.33 p=0.052
ΔSurgery*	rs=0.15 p=0.39	rs=0.10 p=0.54	rs=0.12 p=0.50	rs=0.35 p=0.039	rs=0.32 p=0.055	rs=0.51 p=0.001

Note: *ΔSurgery describes the increase from pre- to post-surgery blood levels. Statistically significant p-values are marked in bold.

Abbreviations: CABG, coronary artery bypass grafting; MPO, myeloperoxidase; MMP, matrix metallopeptidase.