[Polymorphism of angiotensin converting enzyme (ACE) and TNF-beta genes in men with disorders of spermatogenesis--pilot study]

The presence of components of the renin angiotensin system and tumour necrosis factor in a male reproductive tract supports the hypothesis that these substances may influence reproductive functions. It was proved that angiotensin II as a product of ACE has influence on sperm capacitation and motility. TNF-beta is released from T-lymphocytes and has the regulatory effect on steroidogenesis and spermatogenesis. Aberrations of these agents can result in infertility.

The aim of this study was to determine the allele frequency of ACE and TNF-beta genes in men with pathological sperm count and men with normal fertility. We examined the insertion/deletion (I/D) ACE and B1/B2 TNF-beta gene polymorphic alleles and analyzed their frequency in patients and fertile men.

A pilot study.

1st Clinic of Gynaecology and Obstetrics and Institute of Pathologic Physiology, Masaryk University, Brno, CR.

The genomic DNA was isolated from peripheral blood leukocytes by a standard method according to Sambrook in a group of 46 patients (33.4 +/- 7.2 years) with pathological sperm count (9 azoospermia, 21 severe oligoasthenospermia, 16 moderate oligoasthenospermia) and in a control group of 88 healthy men (31.2 +/- 9.3 years) with normal fertility. Polymerase chain reaction (PCR) was used for genom analysis. The method according to Rigat was used for the I/D ACE polymorphism. B1/B2 TNF-beta genotype of each patient was determined after Nco I digestion of the amplified product and subsequent agrose gel electrophoresis. Fisher's exact test and chi square test were used for statistical analysis.

In the study we found these differences of allel frequency and their combination: 1. Combinations of the genotype II (ACE) + B1B2 (TNF-beta) and genotype II (ACE) + B2B2 (TNF-beta) were less frequent in patients (8.7%) than in fertile men (28.4%), this difference was statistically significant (p = 0.021). 2. Allele B1 (TNF-beta) was more frequent among patients (40.2%) than in the control group (29.5%), this difference was near to the point of statistical significance (p = 0.05). 3. Allele D (ACE) frequency was higher in men with pathological sperm count (52.2%) than in fertile men (44.9%), this difference was not statistically significant (p = 0.15).

The study has found different allele frequency of I/D ACE and B1/B2 TNF-beta genes polymorphism in men with pathological sperm count compared to men with normal fertility. These results could contribute to elucidate the genetic background of a male infertility.