Paul J. Turek

Human Embryonic Stem Cell Genes OCT4, NANOG, STELLAR, and GDF3 Are Expressed in Both Seminoma and Breast Carcinoma

The seminoma class of testicular germ cell tumor (TGCT) are characterized by a morphological resemblance to primordial germ cells (PGCs) or gonocytes, and chromosome duplications at 12p. Recently, it was determined that human embryonic stem cells (hESCs) express genes in common with PGCs, and that three of these genes, GDF3, STELLAR, and NANOG, are located on 12p. The current study was designed to identify whether expression of these 12p genes were elevated in seminoma relative to normal testis, and to determine whether elevated expression was unique to seminoma.

Isolation and Characterization of Pluripotent Human Spermatogonial Stem Cell-Derived Cells

Several reports have documented the derivation of pluripotent cells (multipotent germline stem cells) from spermatogonial stem cells obtained from the adult mouse testis. These spermatogonia‐derived stem cells express embryonic stem cell markers and differentiate to the three primary germ layers, as well as the germline. Data indicate that derivation may involve reprogramming of endogenous spermatogonia in culture. Here, we report the derivation of human multipotent germline stem cells (hMGSCs) from a testis biopsy. The cells express distinct markers of pluripotency, form embryoid bodies that contain derivatives of all three germ layers, maintain a normal XY karyotype, are hypomethylated at the H19 locus, and express high levels of telomerase. Teratoma assays indicate the presence of human cells 8 weeks post‐transplantation but limited teratoma formation. Thus, these data suggest the potential to derive pluripotent cells from human testis biopsies but indicate a need for novel strategies to optimize hMGSC culture conditions and reprogramming. STEM CELLS 2009;27:138–149

Human STELLAR, NANOG, and GDF3 Genes Are Expressed in Pluripotent Cells and Map to Chromosome 12p13, a Hotspot for Teratocarcinoma

Genes required to maintain pluripotency in human embryonic stem (hES) cells are largely unknown, with the exception of OCT‐4, a homolog of mouse Oct‐4, which is critical for the establishment of the embryonic inner cell mass and the generation of totipotent mouse embryonic stem (mES) cell lines. In the current study, we identified two genes with expression similar to OCT‐4, in that they are largely restricted to pluripotent hES cells, premeiotic germ lineage cells, and testicular germ cell tumor cells. Furthermore, we determined that upon hES cell differentiation, their expression is downregulated. The genes we identified in the current study include the human stella‐related (STELLAR) gene, which encodes a highly divergent protein (with just 32.1% identity to mouse stella over the 159 amino acid sequence) that maps to human chromosome 12p13. Notably, human STELLAR is located distal to a previously uncharacterized homeobox gene, which is the human homolog of the recently identified murine gene, Nanog, and proximal to the GDF3 locus, whose transcription is restricted to germ cell tumor cells. Our characterization of STELLAR, NANOG, and GDF3 suggests that they may play a similar role in humans as in mice, in spite of their remarkable evolutionary divergence.

Human Pumilio-2 is expressed in embryonic stem cells and germ cells and interacts with DAZ (Deleted in AZoospermia) and DAZ-Like proteins

Early in development, a part of the embryo is set aside to become the germ cell lineage that will ultimately differentiate to form sperm and eggs and transmit genetic information to the next generation. Men with deletions encompassing the Y-chromosome DAZ genes have few or no germ cells but are otherwise healthy, indicating they harbor specific defects in formation or maintenance of germ cells. A DAZ homolog, DAZL (DAZ-Like), is found in diverse organisms, including humans and is required for germ cell development in males and/or females. We identified proteins that interact with DAZ proteins to better understand their function in human germ cells. Here, we show that PUM2, a human homolog of Pumilio, a protein required to maintain germ line stem cells in Drosophila and Caenorhabditis elegans, forms a stable complex with DAZ through the same functional domain required for RNA binding, protein–protein interactions and rescue of Pumilio mutations in flies. We also show that PUM2 is expressed predominantly in human embryonic stem cells and germ cells and colocalizes with DAZ and DAZL in germ cells. These data implicate PUM2 as a component of conserved cellular machinery that may be required for germ cell development.

Increased Risk of Testicular Germ Cell Cancer Among Infertile Men

BACKGROUND The risk of testicular cancer is thought to be higher among men seeking infertility treatment compared with the general population. Confirmation of this risk in a large US cohort of at-risk patients is lacking. This study explored the association between male infertility and subsequent development of testicular cancer in a US-based cohort. METHODS A total of 51 461 couples evaluated for infertility from 1967 to 1998 were recruited from 15 California infertility centers. We linked data on 22 562 identified male partners to the California Cancer Registry. The incidence of testicular cancer in this cohort was compared with the incidence in an age-matched sample of men from the general population using the Surveillance Epidemiology and End Results program. We analyzed the risk for testicular cancer in men with and without male factor infertility using a Cox proportional hazards regression model. RESULTS Thirty-four post-infertility-diagnosis cases of histologically confirmed testicular cancer were identified. Men seeking infertility treatment had an increased risk of subsequently developing testicular cancer (standardized incidence ratio, 1.3; 95% confidence interval, 0.9-1.9), with a markedly higher risk among those with known male factor infertility (2.8; 1.5-4.8). In multivariable analysis, men with male factor infertility were nearly 3 times more likely to develop testicular cancer compared with those without (hazard ratio, 2.8; 95% confidence interval, 1.3-6.0). CONCLUSION Men with male factor infertility have an increased risk of subsequently developing testicular cancer, suggesting the existence of common etiologic factors for infertility and testicular cancer.

CAN VARICOCELECTOMY SIGNIFICANTLY CHANGE THE WAY COUPLES USE ASSISTED REPRODUCTIVE TECHNOLOGIES

PURPOSE We assessed how varicocelectomy alters semen quality in a large cohort of infertile men and determined whether it can change patient candidacy for assisted reproductive technology procedures. MATERIALS AND METHODS A cohort of 540 infertile men with clinical palpable varicocele underwent microsurgical varicocelectomy and were followed more than 1 and 2 years postoperatively for alterations in semen quality and conception, respectively. Preoperatively and postoperatively the total motile sperm count was calculated in all semen analyses. Based on total motile sperm count values patients were divided into 4 groups according to the type of assisted reproductive technology for which they qualified, including 0 to 1.5 million or less (intracytoplasmic sperm injection candidates), 1.5 to 5 million or less (in vitro fertilization candidates), 5 to less than 20 million (intrauterine insemination candidates) and 20 million or greater sperm (spontaneous pregnancy candidates). Preoperative and postoperative semen quality was compared among individuals in these cohorts to determine the shifts in assisted reproductive technology care that are possible after varicolectomy. RESULTS Mean patient age was 29.5 years (range 18 to 58). Microsurgical varicocelectomy was bilateral in 393 patients (73%), on the left side in 146 (27%) and on the right side in 1 (0.2%). A positive response to varicocelectomy, defined as a greater than 50% increase in total motile sperm count, was observed in 271 patients (50%). An overall spontaneous pregnancy rate of 36.6% was achieved after varicocelectomy with a mean time to conception of 7 months (range 1 to 19). Of preoperative in vitro fertilization and intracytoplasmic sperm injection candidates 31% became intrauterine insemination or spontaneous pregnancy candidates after varicolectomy. Of intrauterine insemination candidates 42% gained the potential for spontaneous pregnancy. CONCLUSIONS Varicocelectomy has significant potential not only to obviate the need for assisted reproductive technology, but also to down stage or shift the level of assisted reproductive technology needed to bypass male factor infertility.

Infliximab and Semen Quality in Men With Inflammatory Bowel Disease

Background: Infliximab is effective for induction and maintenance of remission in reproductive age men with Crohns disease. There is no available data on the effects of infliximab on semen quality. The aim of this study was to determine whether changes in semen quality occurred in men receiving infliximab. Methods: In this prospective study, each patient served as his own control. Patients completed general health and fertility questionnaires and were assessed for disease activity. Two semen analyses were completed before infusion with infliximab and 1 semen analysis was completed 1 week after infusion. Mean semen parameters before infusion were compared with postinfusion parameters by paired t tests. Results: Ten men completed the study. Seven were on maintenance infliximab (group 1) and 3 were receiving a first dose (group 2). Seven had Crohns disease, 2 had indeterminate colitis, and 1 had ulcerative colitis. All group 1 patients were in remission. Group 2 patients had moderate or severe disease. In comparing pre‐ and postinfusion semen parameters in all 10 patients, there was a significant increase in semen volume (P = 0.013) after infusion with infliximab and a trend toward decreased sperm motility (P = 0.061). Group 1 had a significant increase in semen volume after infusion (P = 0.039) and a significant decrease in normal oval forms after infusion (P = 0.038). In comparing group 1 and group 2, there was a significant difference in sperm progression. Conclusions: Infliximab therapy in men may decrease sperm motility and the number of normal oval forms. Whether these findings translate into impaired fertility is an area for further study.

Increased Risk of High-Grade Prostate Cancer Among Infertile Men

It has been reported that fatherhood status may be a risk factor for prostate cancer. In the current study, the authors examined the subsequent occurrence of prostate cancer in a cohort of men evaluated for infertility to determine whether male infertility is a risk factor for prostate cancer.

Sexual, marital, and social impact of a man's perceived infertility diagnosis.

INTRODUCTION Male factor infertility is a relatively common problem. This diagnosis may increase sexual, marital, and relationship strain in male partners of infertile couples. AIM To measure the personal, social, sexual, and marital impacts of a male factor infertility diagnosis among men in couples evaluated for infertility. METHODS Cross-sectional analysis of 357 men in infertile couples from eight academic and community-based fertility clinics. Participants completed written surveys and face-to-face and telephone interviews at study enrollment. This interview queried each participants perception of their infertility etiology to determine the primary study exposure (i.e., male factor only, male and female factors, female factor only, unknown). MAIN OUTCOME MEASURES Personal Impact, Social Impact, Marital Impact, and Sexual Impact scales. RESULTS Among the 357 men, no male factor was reported in 47%, isolated male factor was present in 12%, combined male and female factors were present in 16%, and unexplained infertility was present in 25% of couples. Male factor infertility was independently associated with worse Sexual (mean 39 vs. 30, standard deviation [SD] 2.7, P = 0.004) and Personal (mean 37 vs. 29, SD 3.8, P = 0.04) Impact scores relative to men in couples without male factor infertility. These differences remained statistically significant after controlling for male age, partner age, race, religion, educational level, employment status, prior pregnancy, duration of infertility, and prior paternity. CONCLUSIONS Male partners in couples who perceive isolated male factor infertility have a lower sexual and personal quality of life compared with male partners of couples without perceived male factor infertility. Social strain is highest among couples without a clear etiology for infertility. These findings highlight the clinically significant negative sexual, personal, and social strains of a perceived infertility diagnosis for men.

Response to varicocelectomy in oligospermic men with and without defined genetic infertility

OBJECTIVES To compare the clinical characteristics of infertile men who have varicocele with and without a genetic anomaly, and report the results of varicocelectomy in these two cohorts of men. METHODS Study subjects included 33 men who underwent genetic counseling and testing for a diagnosis of oligospermia with varicocele. Seven men were diagnosed with coexisting genetic infertility (genetic [+]; abnormal karyotype in 4, Y chromosome microdeletion in 3), and 26 men with varicocele and no genetic abnormality (genetic [-]). Five patients (Y chromosome microdeletions in 2, abnormal karyotype in 3) in the genetic (+) group and 14 patients in the genetic (-) group underwent microsurgical subinguinal varicocelectomy. Semen and hormonal parameters, physical examination findings, as well as the response to varicocele repair were compared between the two groups. Varicocele response was defined as a 50% increase in total motile sperm count in the ejaculate. RESULTS Mean preoperative seminal and hormonal parameters were not statistically significantly different between the two groups. Significant differences were observed in the volume of the right and left testicles between the two groups (left: P = 0.007; right: P = 0.04). Although 7 of 13 evaluable patients (54%) in the genetic (-) group had a seminal response to varicocelectomy, none of 5 patients in the genetic (+) group showed improvement in semen quality. CONCLUSIONS From this early experience, men with varicocele and genetic lesions appear to have a poorer response to varicocele repair than men without coexisting genetic lesions. These data may have implications for counseling male factor infertility patients contemplating varicocele treatment.