Thesis supervisors:
Associate Professor Margus Punab, MD, PhD, Andrology Centre, Tartu University Hospital
Associate Professor Reet Mändar, MD, PhD, Department of Microbiology, University of Tartu
Opponent:
Professor Giuseppe Morgia, MD, PhD, Professor at the School of Medicine of the University of Catania, Italy
Summary:
The issue of semen quality and fertility in the aging male receives increasing attention due to the following factors. Initially, there is a trend in developed countries toward higher paternal ages predominantly due to socioeconomic factors. Family planning often begins after the establishment of education and professional career, resulting in higher paternal age. Also, the divorce, remarriage, and the wish to be a father of child(s) in a new partnership are increasing trends. Secondly, the improvements in assisted reproduction techniques in recent years, particularly intracytoplasmic sperm injection (ICSI), have endowed to generate genetic offspring in the males (and couples) who were previously considered infertile. At the same time the accumulation of several factors and conditions occurs along with aging that may affect male reproductive function. There are some reports about the impact of paternal occupation on seminal function. Additionally, factors like vascular, hormonal, metabolic and malignant diseases, anatomical and physiological conditions, injuries, lifestyle-related conditions or accumulation of toxic substances may be responsible for alteration in body functioning and therefore also in reproductive function.
Male aging is a multifactorial process that causes changes in different reproductive organs, including the prostate. The prostate, an accessory gland of the male reproductive system, is directly related to male reproductive, sexual, and ejaculatory function. Although some recent studies have described the risk of prostatitis and prostate cancer in middle-aged infertile males, little is known about common associations between reproductive function and prostate pathologies in males over 45 years.
Therefore the main aim of this study was to specify the reproductive function in middle-aged male and to find out possible influences of different prostate conditions and lifestyle-related factors on male reproduction of that age.
The main finding in our study comparing healthy men and male partners of infertile couples was that reproductive function in middle-aged subjects is related not only with general aging as described previously, but associated significantly with certain lifestyle factors, like prior history of sexually transmitted diseases. In addition, fertile men had higher sexual capability and physical activity.
Our study of prostate-related diseases and male reproductive function showed that the increased levels of seminal inflammatory markers were associated with reduced semen volume, total sperm count, and sperm motility. Also, the reduced seminal parameters in middle-aged men were associated with prostate enlargement, bladder outlet obstruction and with pre-malignant and malignant prostate conditions. Probably, the alterations could be related with changes in general health status, malnutrition and gonadal function, but also with subsequent (partial) obstruction in the level of male accessory glands and/or damage of the prostate. Additionally, the serum marker of prostate, PSA, correlated with main seminal parameters like semen volume, sperm motility, and total sperm count. Therefore, according to an initial speculative view, an increased serum level of PSA in middle-aged males could give information not only about prostate-related conditions, but may be an additional indicator for impaired reproductive quality.
The study was performed in the Andrology Centre of Tartu University Hospital.