Significant increase of prostaglandin E-major urinary metabolite in male smokers: a screening study of age and gender differences using a simple radioimmunoassay

Abstract

Background: For the assessment of inflammatory status, we have developed a simple, reliable radioimmunoassay (RIA) of prostaglandin E-major urinary metabolite (PGE-MUM), which remains stable in urine after it is metabolized. Using this method, we conducted a screening study to compare standard values of PGE-MUM to serum C-reactive protein (CRP) levels in health check volunteers.

Methods: PGE-MUM (micrograms per gram creatinine) was measured in normal urine samples obtained from 797 samples in volunteers for health check, using a newly developed RIA, and analyzed in relation to age, gender, smoking, and drinking habits. Results were compared to serum CRP.

Results: PGE-MUM was significantly higher in males than in females. It was significantly higher in smoking males, compared to males who had never smoked (nonsmokers), particularly in those above 40 years of age. In nonsmokers, PGE-MUM declined in males with advancing age, while it rose in females. Although PGE-MUM reflected current smoking status, independent of smoking index (SI), serum CRP indicated both current and former smoking condition, rather dependent upon SI.

Conclusions: PGE-MUM increases in smokers, as suggested by possible inflammatory injury of pulmonary tissue. This RIA method for PGE-MUM may be thus a sensitive and reliable biomarker for current inflammation, different from serum CRP.

Keywords: CRP; age and gender; prostaglandin E-major urinary metabolite; radioimmunoassay; smoking.

Figure 1

Measured HPLC fractions of synthetic PGE‐MUM and human pooled urine by RIA.

Figure 2

Dilution test using three representative urine samples for confirmation of RIA quality.

Figure 3

(A) Comparison of PGE‐MUM by age between males and females in total subjects. (Horizontal bar indicates the median value and box shows 25 and 75% percentile.) (B) Comparison of PGE‐MUM by age between males and females in nonsmokers.

Figure 4

(A) Differences in PGE‐MUM among nonsmokers, former, and current smokers in males (≥5 years: former smokers who quit smoking 5 years or more before the study; <5 years: former smokers who quit smoking less than 5 years before the study). (B) Comparison of PGE‐MUM by age between nonsmokers (never smokers) and current smokers in males. (C) Relation of PGE‐MUM with smoking index in current male smokers.

Figure 5

(A) Comparison of serum CRP by age between males and females in total subjects. (B) Comparison of serum CRP by age between males and females in nonsmokers.

Figure 6

(A) Differences in serum CRP among nonsmokers, former, and current smokers in males (≥5 years: former smokers who quit smoking 5 years or more before the study; <5 years: former smokers who quit smoking less than 5 years before the study). (B) Relation of serum CRP with smoking index in current male smokers.