Evaluation of lung parenchyma, blood vessels, and peripheral blood lymphocytes as a potential source of acute phase reactants in patients with COPD

Figures & data

Table 1 Primers used for reverse transcription quantitative PCR

Gene	Forward primer	Reverse primer
18S	5ʹ-TGAAATATCCAGAACATCTTA-3’	5ʹ-GCAAAATTTATTGTCCCATCAT-3’
CRP	5ʹ-GTGTTTCCCAAAGAGTCGGATA-3’	5ʹ-CCACGGGTCGAGGACAGTT-3’
SAA1	5ʹ-ATCAGCGATGCCAGAGAGAAT-3’	5ʹ-GTGATTGGGGTCTTTGCCA-3’
SAA2	5ʹ-AGCCAATTACATCGGCTCAG-3’	5ʹ-ATTTATTGGCAGCCTGATCG-3’
SAA4	5ʹ-GTCCAACGAGAAAGCTGAGG-3’	5ʹ-AGTGACCCTGTGTCCCTGTC-3’

Table 2 General characteristics of the study participants

	Control group (n=62)	COPD patients (n=40)	P-value*
Males (n)	48 (77.4%)	37 (92.5%)	0.029
Age (years)	64.4±13.5	67.4±8.01	NS
Tobacco history (pack-years)	43.5±34.7	69.7±33.1	0.001
Current smokers/former smokers	13/27	17/45	NS
Charlson-age index	4.9±2.2	5.7±1.7	NS
FVC (%)	98.7±20.45	91.6±19	NS
FEV1 (%)	94.0±19.89	69.0±18.4	<0.001
FEV1/FVC (%)	77.1±6.9	59.0±9.7	<0.001
Oral steroids	77.1±6.9	7 (17.5%)	<0.001
Combinations including an inhaled corticosteroid	0 (0%)	14 (35.0%)	0.029

Notes: Data are expressed as means and SDs for continuous variables and frequencies and percentages for categorical variables. *P-values were calculated with the Student’s t-test (continuous variables) or the χ² test (categorical variables).

Abbreviation: NS, not significant.

Table 3 Correlations between expressions of acute phase reactant

	Pulmonary parenchyma	Pulmonary artery	Peripheral blood leukocytes
CRP-SAA1 mRNA	r=0.448 P<0.001	r=0.314 P=0.001	r=0.510 P<0.001
CRP-SAA2 mRNA	r=0.105 P=NS	r=0.229 P=0.020	r=0.163 P=NS
CRP-SAA4 mRNA	r=0.496 P<0.001	r=0.320 P=0.001	r=0.394 P<0.001
SAA1-SAA2 mRNA	r=0.508 P<0.001	r=0.513 P<0.001	r=0.101 P=NS
SAA1-SAA4 mRNA	r=0.609 P<0.001	r=0.170 P=NS	r=0.744 P<0.001
SAA2-SAA4 mRNA	r=0.4290 P<0.001	r=−0.001 P=NS	r=0.019 P=NS

Note: Correlations were calculated using the Spearman’s rank correlation coefficient.

Abbreviations: CRP,C-reactive protein; SAA, serum amyloid A

Figure 1 Gene expression in COPD patients and control group. Gene expression of acute phase reactants in resistant smokers (controls) and COPD patients in lung parenchyma (panel A). SAA4 expression profile in the lung parenchyma according to COPD stage (Panel B). I, GOLD I COPD; II, GOLD II COPD; III, GOLD III COPD. No statistically significant differences were identified (P>0.05).

Abbreviations: CNT, resistant smokers (controls); SAA, serum amyloid A.

Figure 2 Gene expression in COPD patients and control group. Gene expression of acute phase reactants in resistant smokers (controls) and COPD patients in pulmonary artery (panel A). SAA2 expression profile in the pulmonary artery according to COPD stage (B). I, GOLD I COPD; II, GOLD II COPD; III, GOLD III COPD. No statistically significant differences were identified (P>0.05).

Abbreviations: CNT, resistant smokers (controls); SAA, serum amyloid A.

Figure 3 Gene expression of acute phase reactants in resistant smokers (controls) and COPD patients in blood cells (A). SAA1 (Panel B) and SAA4 (Panel C) expression in blood cells according to COPD stage. I, GOLD I COPD; II, GOLD II COPD; III, GOLD III COPD. No statistically significant differences were identified (P>0.05).

Abbreviations: CNT, resistant smokers (controls); SAA, serum amyloid A.

Figure 4 Comparison of acute phase reactants gene expression levels in different tissues (blood cells, pulmonary artery, and lung parenchyma) of COPD patients. Panel (A): CRP expression; panel (B): SAA2 expression; panel (C): SAA1 expression and panel (D): SAA4 expression.

Abbreviations: CRP, C-reactive protein; SAA, serum amyloid A.

Table 4 Correlations between different tissues

	r	p
CRP parenchyme-CRP artery	0.195	0.04
SAA1 parenchyme-SAA1 leukocytes	0.743	<0.001
SAA4 parenchyme-SAA4 leukocytes	0.980	<0.001
SAA1 parenchyme-SAA4 leukocytes	0.758	<0.001
SAA4 parenchyme-SAA1 leukocytes	0.966	<0.001

Note: Correlations were calculated using the Spearman’s rank correlation coefficient.

Abbreviations: CRP, C-reactive protein; SAA, serum amyloid A.

Figure 5 Plasma concentrations of serum amyloid A (SAA) (panel A) and CRP (panel B) in CNTs and patients with different stages of COPD.

Abbreviations: CRP, C-reactive protein; CNT, resistant smokers (controls).

Figure 6 Immunostaining of C-reactive protein (CRP) and serum amyloid A (SAA) in lung biopsies of patients. Pulmonary parenchyma stained with CRP of a COPD (panel A) and control (panel B). Pulmonary parenchyma stained with SAA of COPD patient (panel C) and control patients (panel D). Scale bar represents 100 μm in each case.