Serum Derivatives of Reactive Oxygen Metabolites are Associated with Severity of Chronic Obstructive Pulmonary Disease and Affected by a p53 Gene Polymorphism

Figures & data

Table 1 Patient Characteristics

Characteristic	Smoker Controls	Mild COPD	Moderate COPD	Severe COPD	p value
GOLD	…	Stage I	Stage II	Stage III/IV	–
No. of patients	95	41	62	48 (39/9)	–
Age, years	70.5 ± 9.4	71.1 ± 9.6	72.0 ± 8.9	73.6 ± 7.8	0.271
Sex, male (female)	92 (3)	38 (3)	62 (0)	45 (3)	0.179
Smoking, pack-years	58.5 ± 37.6	54.7 ± 32.8	64.1 ± 35.9	67.2 ± 31.6	0.293
Current smoker, NO	36	15	22	11	0.328
%FVC, predicted	97.3 ± 13.7	113.6 ± 14.3*	95.8 ± 13.9^†	76.8 ± 17.2*^†‡	<0.0001
FEV1/FVC, %	77.4 ± 5.8	64.5 ± 4.7 *	54.3 ± 8.9*^†	39.9 ± 11.3*^†‡	<0.0001
%FEV1, predicted	96.0 ± 13.1	95.2 ± 13.1	66.7 ± 8.6*^†	37.9 ± 8.1*^†‡	<0.0001
LAA%	5.0 ± 6.1	9.8 ± 8.7*	13.0 ± 10.3*	21.7 ± 15.5*^†‡	<0.0001
BMI (kg/m^2)	23.7 ± 3.7	23.8 ± 2.8	23.2 ± 3.2	21.5 ± 3.6*^†	0.0026
ESMCSA (cm^2)	2979 ± 833.5	3138 ± 607.6	2788 ± 755.2	2466 ± 756.9*^†	0.0002
Cr/CysC ratio	0.86 ± 0.15	0.91 ± 0.18	0.88 ± 0.15	0.78 ± 0.14*^†‡	0.0003
HsCRP (mg/dL)	0.183 ± 0.205	0.192 ± 0.186	0.218 ± 0.227	0.345 ± 0.292*^†‡	0.0007

Notes: Values are expressed as mean ± SD. *p<0.05 versus smoker controls. ^†p<0.05 versus mild COPD, ^‡p<0.05 versus moderate COPD.

Abbreviations: COPD, Chronic obstructive pulmonary disease; GOLD, Global Initiative for Obstructive Lung Disease; %FVC, predicted, percent forced vital capacity, predicted; %FEV1, predicted, percent forced expiratory volume in 1 second, predicted; body mass index, BMI; ESM_CSA, cross-sectional area of erector spinae muscles; Cr, creatinine; Cys C, cystatin C; HsCRP, high-sensitivity C-reactive protein.

Figure 1 Representative photograph of PCR-RFLP analysis of p53 gene codon 72 polymorphisms. PCR-amplified genomic DNA corresponding to the p53 gene was digested with BstUI, which distinguishes among p53 genotypes. Lane 1 shows the DNA ladder marker, lane 2 shows the PCR product without restriction digestion, lane 3 shows the p53 codon 72 CC genotype, lane 4 shows the GG genotype, and lane 5 shows the CG genotype.

Figure 2 Derivatives of reactive oxygen metabolites (d-ROMs) (A), biological antioxidant potential (BAP) (B), and oxidative stress index (OSI) (C) in serum from smoker controls (control) and patients with moderate chronic obstructive pulmonary disease (COPD) (moderate), mild COPD (mild), and severe COPD (severe). d-ROM levels and OSI were significantly higher in patients with severe COPD compared with the control and moderate COPD patient groups. No significant differences were observed in BAP between the groups. Data are expressed as mean ± SD.

Figure 3 D-ROM levels (A), BAP (B), OSI (C), and high-sensitivity C-reactive protein (HsCRP) levels (D) in serum from current and ex-smokers. Data are expressed as mean ± SD. BAP was significantly increased and OSI significantly decreased in ex-smokers compared with current smokers.

Figure 4 Results of correlation analyses between d-ROM levels and percent forced vital capacity, predicted (%FVC) (A), percent forced expiratory volume in 1 second, predicted (%FEV1) (B), percent low-attenuation area (LAA%) (C), and between OSI and %FVC (D), %FEV1 (E), and LAA% (F). d-ROM levels were weakly correlated with %FVC and %FEV1.

Figure 5 Results of correlation analyses between d-ROM levels and body mass index (BMI) (A), cross-sectional area of the erector spinae muscles (ESM_CSA) (B), creatinine/cystatin C ratio (Cr/CysC ratio) (C), and between OSI and BMI (D), ESM_CSA (E), and Cr/CysC ratio (F). d-ROM levels and OSI were weakly correlated with ESM_CSA and Cr/CysC ratio.

Table 2 Characteristics of Patients Categorized by p53 Codon 72 Genotype

	p53 Codon 72 CC	p53 Codon 72 CG	p53 Codon 72 GG	p value
No. of patients	41	116	89	–
Age, years	71.3 ± 9.1	72.4 ± 9.4	70.6 ± 8.6	0.385
Smoking, pack-years	64.7 ± 28.3	58.6 ± 32.0	62.4 ± 41.9	0.566
Current smoker, NO	17	42	25	0.266
Sex, male (female)	40 (1)	110 (6)	87 (2)	0.489
%FVC, predicted	101.2 ± 16.2	94.5 ± 19.1	94.6 ± 17.9	0.104
FEV1/FVC, %	66.4 ± 13.9	60.7 ± 15.7	62.0 ± 17.8	0.153
%FEV1, predicted	86.6 ± 22.3	74.6 ± 26.0 *	75.3 ± 25.6	0.027
LAA%	7.6 ± 8.2	10.8 ± 11.8	13.1 ± 12.6 *	0.041
BMI (kg/m^2)	23.4 ± 3.1	22.9 ± 3.4	23.5 ± 3.8	0.412
ESMCSA (cm^2)	2968 ± 762.2	2841 ± 757.5	2828 ± 854.5	0.616
Cr/CysC ratio	0.90 ± 0.17	0.86 ± 0.17	0.87 ± 0.14	0.404
d-ROM (U. CARR)	324.0 ± 67.0	327.2 ± 56.4	327.2 ± 69.4	0.956
BAP (μmol/L)	2152 ± 335.2	2141 ± 224.7	2146 ± 207.1	0.967
OSI (d-ROM/BAP)	0.154 ± 0.04	0.155 ± 0.003	0.153 ± 0.03	0.926
HsCRP (mg/dL)	0.238 ± 0.234	0.213 ± 0.228	0.235 ± 0.242	0.733

Note: Values are expressed as mean ± SD. *p<0.05 versus p53 codon 72 CC.

Abbreviations: d-ROM, derivatives of reactive oxygen metabolites; BAP, biological anti-oxidant potential; OSI, oxidative stress index.

Table 3 p53 Genotype Frequencies in COPD Patients

p53 Codon 72 Genotype
	CC	CG	GG	p value
Smoker Control	22 (23.2%)	37 (38.9%)	36 (37.9%)	Reference
Mild COPD	7 (17.1%)	21 (51.2%)	13 (31.7%)	0.994
Moderate COPD	8 (12.9%)	34 (54.8%)	20 (32.3%)	0.695
Severe COPD	4 (8.3%)	24 (50.0%)	20 (41.7%)	0.149

Table 4 p53 Allele Frequencies in COPD Patients

p53 Codon 72 Allele
	C	G	p value	Odds Ratio (95% CI)
Smoker Control	42.6%	57.4%	Reference
Mild COPD	42.7%	57.3%	1.000	0.998 (0.59–1.69)
Moderate COPD	40.3%	59.7%	0.726	1.100 (0.69–1.74))
Severe COPD	33.3%	66.7%	0.159	1.486 (0.89–2.48)

Abbreviation: CI, confidence interval.

Figure 6 D-ROM levels in serum from smoker controls (control) and patients with moderate COPD (moderate), mild COPD (mild), and severe COPD (severe) carrying the p53 codon 72 CC genotype (A), CG genotype (B), and GG genotype (C). BAP of serum from controls and patients with moderate, mild, and severe COPD carrying the p53 codon 72 CC genotype (D), CG genotype (E), and GG genotype (F). OSI in serum from patients carrying p53 codon 72 CC genotype (G), CG genotype (H), and GG genotype (I). Data are expressed as mean ± SD. d-ROM levels and OSI in patients with severe COPD were significantly increased among those carrying the GG genotype compared with control subjects and patients with moderate and mild COPD. Only among patients with mild COPD carrying the CC genotype were d-ROM levels increased compared with control subjects.

Figure 7 Results of correlation analyses between d-ROM levels and LAA% in patients carrying the p53 codon 72 CC genotype (A), CG genotype (B) and GG genotype (C). d-ROM levels were weakly correlated with LAA% in patients carrying the GG genotype.