Androgen receptor (AR)-CAG trinucleotide repeat length and idiopathic male infertility

CAG trinucleotide repeats in androgen receptor (AR) gene encode a polyglutamine tract in AR N-terminal transactivation domain. Studies have been conducted to evaluate the effect of CAG repeat length on male infertility, which have yielded contradictory results. This study aimed to explore the number of AR-CAG repeats in 150 fertile controls and 150 idiopathic infertile men, divided into four azoospermia, oligozoospermia, asthenozoospermia, and teratozoospermia subgroups. In addition, a meta-analysis was conducted based on previous studies to assess the association of the mentioned variation with male infertility in recent years. Polymerase chain reaction (PCR) targeting followed by an electrophoresis on polyacrylamide gel was used for AR-CAG genotype detecting. Moreover, a systematic search was performed in PubMed, Web of Science, Science Direct, and Google Scholar databases to collect eligible studies for meta-analysis purpose. According to the results, a significant association was observed between increased length of AR-CAG polymorphism and male infertility (p< 0.0001). Furthermore, there were similar significant associations in the azoospermia (p= 0.048), asthenozoospermia (p= 0.013) and teratozoospermia (p= 0.002) subgroups. In addition, meta-analysis on forty studies showed a significant association between AR-CAG polymorphism in the overall analysis (SMD= 0.199, 95 % CI= 0.112-0.287, p<0.001) and the Caucasian subgroup (SMD= 0.151, 95 % CI= 0.040-0.263, p= 0.008). Our results elucidated that long stretches of CAG repeat might lead to AR dysfunction, contributing to male infertility especially in the Caucasian population

Validierung eines Immunoassays für Inhibin B im Serum und Korrelation der Meßwerte mit allelischen Varianten des Follikelstimulierenden Hormon-Rezeptors bei fertilen und infertilen Männern

Inhibin B, negativer Feedback-Regulator der FSH Ausschüttung, fungiert als "Marker" der Spermatogenese. Gebildet in Sertoli-Zellen, ist die Ausschüttung von der Funktionsfähigkeit der FSH-Rezeptoren abhängig. Veränderungen des FSH-Rezeptors könnten zu unterschiedlichen Inhibin-Werten führen. Mittels eines spezifischen Inhibin B ELISAs sollten fertile und infertile Männer in Abhängigkeit der FSH-Rezeptorvariante verglichen werden. Zunächst Validierung des Inhibin B ELISA, anschließend Messung des Inhibin B im Serum. Ziele: 1) Bestätigung der negativen Korrelation zwischen Inhibin B und FSH, 2) Lassen Inhibin B Werte Aussagen über den FSH-Rezeptortyp zu, 3) Kommen Rezeptorvarianten als Ursache der Infertilität in Frage und ist dies über die Inhibin B Werte quantifizierbar. Ergebnisse: 1) Negative Korrelation in beiden Gruppen nachweisbar. 2) Kein signifikanter Unterschied in Abhängigkeit des FSH-Rezeptortyps. 3) Polymorphismus des FSH-Rezeptors ist keine Ursache männlicher Infertilität

Genetic, environmental and life-style effects on androgen receptor function

Androgens regulate male reproductive function and their effects are mediated through the androgen receptor (AR). The AR gene contains a polymorphic CAG repeat, encoding a stretch of glutamines, affecting the transcriptional activity of the AR. Prostate specific antigen (PSA) is a downstream target and is commonly used in the screening of prostate cancer. The relationship between CAG number and male reproductive health has been suggested to be modulated by persistent organic pollutants (POPs). Humans are exposed mainly through food intake, but also from industrial processes and cigarette smoking. The dioxin-like POPs exert their effect through the aryl hydrocarbon receptor (AhR), shown to interact with the AR. The aims were to study the role of the CAG polymorphism on; AR activity and expression in the absence or presence of POPs; PSA concentration in serum and tissue; and reproductive parameters and hormones in men. It was also elucidated whether the CAG number could modify the effect of cigarette smoking on reproductive characteristics in men. The transactivation assay included a reporter gene with a human androgen responsive promoter. Cells were transfected with vectors having CAG numbers of 16, 22 or 28, representative of the human range. To explore the association between CAG number and reproductive outcome, an unprejudiced spline regression model with CAG number as a continuous variable was used, as well as a stratified model and in case of linear pattern, CAG number was investigated in a linear regression model. We found that the CAG variant with the median length had the highest AR activity, shown both in cell lines and prostate tissue, and as highest PSA concentration in younger and older men. The unprejudiced statistical analysis gave a better picture of the relationship between CAG number and reproductive outcomes, demonstrating a CAG-dependent effect on hormone levels. The CAG repeat also had a cell line- and dose-dependent modulating effect of POPs on AR activity and was negatively associated with semen volume in smoking men. To conclude, the median AR CAG number had the highest activity in vivo and in vitro. This pattern consisted even in the presence of POPs, indicating a stronger resistance for the median CAG length to these compounds compared to less common variants. The CAG number was also associated with reproductive hormone regulation and might modify the susceptibility of current cigarette smoking on semen volume in young men

Polycystic Ovary Syndrome: Pathophysiology, Phenotype Expression and Clinical Implications

Annemarie Geerdina Maria Geertruida Johanna Mulders was born on the 29th of April 1972 in Waalwijk, The Netherlands. She passed secondary school at the Dr. Mollercollege in Waalwijk. She attended Medical School at the Erasmus University in Rotterdam from 1992 - 1999 from which she graduated cum laude. From December 1999 - August 2000 she worked as a resident at the department of Obstetrics and Gynaecology of the Sint Lucas Andreas Hospital (head: Dr. J.Th.M. van der Schoot) in Amsterdam. From August 2000 -December 2003 she worked as a PhD student at the division of Reproductive Medicine (head: Prof. Dr. B.C.J.M. Fauser) of the department of Obstetrics and Gynaecology of the Erasmus MC in Rotterdam performing the studies described in this thesis. In January 2004 she started her training in Obstetrics and Gynaecology at the Amphia Hospital in BredaPolycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive age women and a major cause of subfertility. Women with PCOS might present with a number of various features and hence PCOS does not seem to be a clear-cut clinical phenomenon. In order to elucidate the background and pathophysiology of all symptoms displayed in PCOS it might be helpful to focus on these specific characteristics and features. In this chapter pathophysiology of ovarian dysfunction is highlighted. Additionally, several characteristic PCOS features used for classification and involved in phenotypical heterogeneity, will be briefly described. Furthermore, the complexity of research regarding the genetic c

Polycystic Ovary Syndrome: Pathophysiology, Phenotype Expression and Clinical Implications

Annemarie Geerdina Maria Geertruida Johanna Mulders was born on the 29th of April 1972 in Waalwijk, The Netherlands. She passed secondary school at the Dr. Mollercollege in Waalwijk. She attended Medical School at the Erasmus University in Rotterdam from 1992 - 1999 from which she graduated cum laude. From December 1999 - August 2000 she worked as a resident at the department of Obstetrics and Gynaecology of the Sint Lucas Andreas Hospital (head: Dr. J.Th.M. van der Schoot) in Amsterdam. From August 2000 -December 2003 she worked as a PhD student at the division of Reproductive Medicine (head: Prof. Dr. B.C.J.M. Fauser) of the department of Obstetrics and Gynaecology of the Erasmus MC in Rotterdam performing the studies described in this thesis. In January 2004 she started her training in Obstetrics and Gynaecology at the Amphia Hospital in BredaPolycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive age women and a major cause of subfertility. Women with PCOS might present with a number of various features and hence PCOS does not seem to be a clear-cut clinical phenomenon. In order to elucidate the background and pathophysiology of all symptoms displayed in PCOS it might be helpful to focus on these specific characteristics and features. In this chapter pathophysiology of ovarian dysfunction is highlighted. Additionally, several characteristic PCOS features used for classification and involved in phenotypical heterogeneity, will be briefly described. Furthermore, the complexity of research regarding the genetic c

Human cumulus cell expression profile of AMH, AMHR2, FSHR and AR genes in predicting oocyte fertilization potential

Temelj uspješnosti medicinski pomognute oplodnje je pravilno sazrijevanje jajnih stanica. Na kvalitetu jajne stanice velik utjecaj ima okruženje u kojem se ona nalazi, tzv. mikrookoliš koji uključuje stanice kumulusa i folikularnu tekućinu. Određivanje pojedinih komponenti tog mikrookoliša koje se jednostavno i brzo mogu detektirati, a koje omogućavaju razlikovanje kvalitete jajnih stanica, doprinijelo bi povećanju uspješnosti metoda pomognute oplodnje. Anti-Müllerov hormon (AMH) je glikoproteinski faktor rasta, koji luče stanice kumulusa. S obzirom na njegovu ulogu u folikulogenezi, ovim je doktorskim radom istražen ekspresijski profil ovog gena, i s njim povezanih receptora (AMHR2, FSHR i AR), te njihova korelacija s kvalitetom jajnih stanica u postupku medicinski pomognute oplodnje, odnosno s morfološkim karakteristikama jajnih stanica, zigota i embrija te njihovim fertilizacijskim potencijalom. U istraživanje je uključeno 129 uzoraka stanica kumulusa i 35 uzoraka folikularne tekućine koji su sakupljeni od ukupno 52 pacijentice u postupku medicinski pomognute oplodnje. Primijenjena je metoda relativne kvantifikacije genskih ekspresija istraživanih gena u stanicama kumulusa, enzimatski pojačani dvostruki imunološki test (ELISA) za određivanje koncentracije AMH u folikularnoj tekućini istog folikula te morfološka analiza jajnih stanica, zigota i embrija invertnom mikroskopijom. Rezultati dobiveni istraživanjem po prvi put ukazuju na negativnu povezanost ekspresije AMH i AR gena u stanicama kumulusa s morfološkom kvalitetom pripadajuće jajne stanice, odnosno s njenom zrelošću. Osim navedenog, istraživanjem je utvrđeno i postojanje korelacija među ekspresijama ispitivanih gena: između FSHR gena i svih ostalih istraživanih gena (AMH, AMHR2 i AR), između AMHR2 i AR gena, te između AMH i AR gena. Dobiveni rezultati pridonose razjašnjenju potencijalne veze AMH (i receptora koji su na direktni ili manje direktni način povezani s ovim hormonom) i morfološke kvalitete jajne stanice. Istraživanjem je potvrđena važnost kompleksa kumulusa i oocite, odnosno komunikacije između jajne stanice i njenog mikrookoliša, za razvoj kvalitetne oocite koja je preduvjet za uspješnu oplodnju i razvoj kvalitetnog embrija.The core notion determining the success rate of the medically assisted reproduction is the right growth of the oocytes. The environment, or the so called microenvironment, greatly influences the quality of the oocyte and it includes the cumulus cells and the follicular fluid. Determining the specific components of this microenvironment, which can be easily and swiftly detected, and which enable us to distinguish between good and bad quality oocytes, would contribute to the success rate of the medically assisted reproduction. Anti-Müllerian hormone is a glycoprotein growth factor emitted by the cumulus cells. Considering its role in the folliculogenesis, this doctoral thesis looked into the expression profile of the stated gene and its respective receptors. Their correlation with the oocyte quality in the process of medically assisted reproduction was examined, as well as morphological characteristics of the oocytes, zygotes and embryos together with their fertilization potential. The research included 129 cumulus cells samples and 35 follicular fluid samples which had been harvested from 52 patients during the process of medically assisted reproduction. The method of relative quantification of gene expressions in the cumulus cells for the researched genes was employed, the enzyme - linked immunosorbent assay (ELISA) was used to determine the concentration of AMH in the follicular fluid of the respective follicle, and the morphological analysis of the oocytes, zygotes and embryos was conducted by inverted microscopy. The results obtained in the research for the first time show the negative correlation between the AMH and AR genes expression in the cumulus cells and the morphological quality, i.e. maturity, of the respective egg cell. Furthermore, the research determined the existence of correlations between the expressions of the examined genes as follows: between FSHR genes and all the other researched genes (AMH, AMHR2 and AR), between AMHR2 and AR genes, as well as between AMH and AR genes. The obtained results also contribute to the clarification of the potential connection between AMH (and the receptors directly or less directly linked to this hormone) and morphological quality of the egg cell. The research confirmed the importance of the cumulus - oocyte complex, i.e. of the communication between the egg cell and its microenvironment, for the growth of a high - quality oocyte, which is a prerequisite for a successful fertilization and growth of a high - quality embryo