Relationship between angiotensin I converting enzyme gene polymorphism and serum angiotensin I converting enzyme activity in patients with silicosis

Abstract

Objective To investigate the relationship between the insertion/deletion polymorphism (including three genotypes II, ID and DD) in the 16th intron of angiotensin Ⅰconverting enzyme (ACE) gene and the serum ACE activity in patients with silicosis. Methods 114 patients with silicosis in Meitan General Hospital and 109 healthy control subjects were collected from July 2011 to April 2016.The serum ACE activity was measured by enzyme linked immunosorbent assay.The genotyping of ACE gene polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism in silicosis group and healthy control group. Results There was no significant difference in the genotype distribution of ACE gene polymorphism between silicosis group and healthy control group.The serum ACE activity among the three genotypes was significant difference in silicosis group and healthy control group (all P<0.01). There was significant difference between ID and DD genotypes in silicosis group (P<0.01), whereas there was no difference between the same two genotypes in healthy control group.In silicosis group, the percentage of the II, ID, DD genotypes was 38.6% (44 cases), 43.0% (49 cases) and 18.4% (21 cases), respectively.The serum ACE activity in the patients with ID genotype was the highest [37.24 (22.96, 43.90) U], the second was DD genotype [24.76 (20.02, 29.80) U], the lowest was II genotype [20.46 (14.53, 30.51) U]. On the other hand, in healthy controls, the percentage of the II, ID, DD genotypes was 44.0% (48 cases), 44.0% (48 cases), and 11.9% (13 cases), respectively.The serum ACE activity was the highest in healthy controls with ID genotype [26.64 (18.15, 31.71) U], the second was DD genotype [19.92 (16.96, 24.16) U], the lowest was II genotype [13.48 (10.54, 16.69) U]. The serum ACE activity in the patients with ID and II genotypes was higher than that in the healthy controls with the same two genotypes (U=427.5, 651.0, all P<0.01). The serum ACE activity in silicosis group was significantly higher than that in healthy control group (P<0.01). There was no correlation between ACE gene polymorphism and the lung function (OR=0.98, 95% CI: 0.91-1.07, P=0.941). There was no correlation between ACE gene polymorphism and the stage of silicosis (OR=0.91, 95%CI: 0.05-18.18, P=0.736). Conclusions ACE gene polymorphisms influences the serum ACE activity in patients with silicosis.It is speculated that the morbidity incidence of silicosis may be related to high ACE activity. Key words: Silicosis; Angiotensin Ⅰ converting enzyme gene; Polymorphism; Angiotensin Ⅰ converting enzyme activity