Dimitrios Baltogiannis

Hormonal regulation of spermatogenesis and spermiogenesis.

Normal testicular function is dependent upon hormones acting through endocrine and paracrine pathways both in vivo and in vitro. Sertoli cells provide factors necessary for the successful progression of spermatogonia into spermatozoa. Sertoli cells have receptors for follicle stimulating hormone (FSH) and testosterone which are the main hormonal regulators of spermatogenesis. Hormones such as testosterone, FSH and luteinizing hormone (LH) are known to influence the germ cell fate. Their removal induces germ cell apoptosis. Proteins of the Bcl-2 family provide one signaling pathway which appears to be essential for male germ cell homeostasis. In addition to paracrine signals, germ cells also depend upon signals derived from Sertoli by direct membrane contact. Somatostatin is a regulatory peptide playing a role in the regulation of the proliferation of the male gametes. Activin A, follistatin and FSH play a role in germ cell maturation during the period when gonocytes resume mitosis to form the spermatogonial stem cells and differentiating germ cell populations. In vitro cultures systems have provided evidence that spermatogonia in advance stage of differentiation have specific regulatory mechanisms that control their fate. This review article provides an overview of the literature concerning the hormonal pathways regulating spermatogenesis.

Penetration of Antimicrobial Agents into the Prostate

In the present review article, the penetration of antimicrobial agents into prostatic fluid and tissue was examined. Three major factors determining the diffusion and concentration of antimicrobial agents in prostatic fluid and tissue are the lipid solubility, dissociation constant (pKa) and protein binding. The normal pH of human prostatic fluid is 6.5–6.7, and it increases in chronic prostatitis, ranging from 7.0 to 8.3. A greater concentration of antimicrobial agents in the prostatic fluid occurs in the presence of a pH gradient across the membrane separating plasma from prostatic fluid. Of the available antimicrobial agents, β-lactam drugs have a low pKa and poor lipid solubility, and thus penetrate poorly into prostatic fluid, expect for some cephalosporins, which achieve greater than or equal to the inhibitory concentration. Good to excellent penetration into prostatic fluid and tissue has been demonstrated with many antimicrobial agents, including tobramycin, netilmicin, tetracyclines, macrolides, quinolones, sulfonamides and nitrofurantoin.

Effects of paternal cigarette smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation in rats

Summary. We evaluated the effects of paternal smoking on testicular function, sperm fertilizing capacity, embryonic development, and blastocyst capacity for implantation. Rats of group A were exposed to cigarette smoke for 10 weeks. Rats of group B were exposed to the smoke of incense sticks for 10 weeks. Rats of group C served as a control group. Rats of group D were exposed to cigarette smoke for 7 weeks only. Experimental period was 10 weeks in all groups. At the end of the experimental period serum testosterone responses to human chorionic gonadotropin stimulation, andro‐gen‐binding protein activity in testicular cytosols, epididymal sperm motility, and oocyte fertilization rate, oocyte cleavage rate, and blastocyst development rate after in vitro fertilization (IVF) trials were significantly smaller in group A compared with groups B and C. In contrast, fertilization rate, cleavage rate, and blastocyst development rate after intracytoplasmic sperm injection (ICSI) procedures were not significantly different among groups A, B, C, and D. Both after IVF trials and ICSI techniques, the proportion of the alive offspring to the number of transferred oocytes was significantly smaller in group A than in groups B and C. Cigarette smoke‐exposure results in a secretory deficiency of Leydig and Sertoli cells leading to an impaired epididymal sperm maturation process and diminished capacity of spermatozoa to penetrate oocytes. In addition paternal cigarette smoke exposure affects the embryonic ability for implantation.

Effects of phosphodiesterase 5 inhibitors on sperm parameters and fertilizing capacity

The aim of this review study is to elucidate the effects that phosphodiesterase 5 (PDE5) inhibitors exert on spermatozoa motility, capacitation process and on their ability to fertilize the oocyte. Second messenger systems such as the cAMP/adenylate cyclase (AC) system and the cGMP/guanylate cyclase (GC) system appear to regulate sperm functions. Increased levels of intracytosolic cAMP result in an enhancement of sperm motility and viability. The stimulation of GC by low doses of nitric oxide (NO) leads to an improvement or maintenance of sperm motility, whereas higher concentrations have an adverse effect on sperm parameters. Several in vivo and in vitro studies have been carried out in order to examine whether PDE5 inhibitors affect positively or negatively sperm parameters and sperm fertilizing capacity. The results of these studies are controversial. Some of these studies demonstrate no significant effects of PDE5 inhibitors on the motility, viability, and morphology of spermatozoa collected from men that have been treated with PDE5 inhibitors. On the other hand, several studies demonstrate a positive effect of PDE5 inhibitors on sperm motility both in vivo and in vitro. In vitro studies of sildenafil citrate demonstrate a stimulatory effect on sperm motility with an increase in intracellular cAMP suggesting an inhibitory action of sildenafil citrate on a PDE isoform other than the PDE5. On the other hand, tadalafils actions appear to be associated with the inhibitory effect of this compound on PDE11. In vivo studies in men treated with vardenafil in a daily basis demonstrated a significantly larger total number of spermatozoa per ejaculate, quantitative sperm motility, and qualitative sperm motility; it has been suggested that vardenafil administration enhances the secretory function of the prostate and subsequently increases the qualitative and quantitative motility of spermatozoa. The effect that PDE5 inhibitors exert on sperm parameters may lead to the improvement of the outcome of assisted reproductive technology (ART) programs. In the future PDE5 inhibitors might serve as adjunct therapeutical agents for the alleviation of male infertility.

Orbital Metastasis from Prostatic Carcinoma

A rare case of orbital metastasis from carcinoma of the prostate in a 76-year-old man who presented with pain in his left eye, mild proptosis and reduced visual acuity is reported. Cranial CT scanning demonstrated large bone metastases in the left orbit. The patient underwent orbital evisceration. The histopathological studies that were based on the morphological and immunohistochemical findings confirmed the histological diagnosis of orbital metastasis arising from prostatic carcinoma with neuroendocrine features.

Role of testicular tissue telomerase assay for the prediction of the presence of testicular spermatozoa in azoospermic men with varicoceles, pre- and post-varicocelectomy.

Summary.  We evaluated the reproductive potential of frozen/thawed testicular spermatozoa of azoospermic men with left varicocele. The role of testicular tissue telomerase assay (TTA) in the prediction of the presence of testicular spermatozoa pre‐ and post‐varicocelectomy was investigated, as well. Therapeutic testicular biopsy and TTA were performed in 82 nonobstructed azoospermic (NOA) men with varicoceles. Testicular spermatozoa were found in 33 men and processed for cryopreservation. Oocytes were later recovered from the spouses of the latter azoospermic men with varicoceles and injected with frozen/thawed testicular spermatozoa. Among the 49 men who were negative for testicular spermatozoa, 22 men underwent subsequently subinguinal microsurgical varicocelectomy. A total of 198 mature oocytes were successfully injected and 101 were normally fertilized and subsequently cleaved. Transfer of these 101 embryos in 26 women resulted in nine full‐term pregnancies. Thirteen healthy babies were delivered. A cut‐off value of TTA of 39 TPG U μg−1 protein had an overall diagnostic accuracy equal to 90.2% to predict the presence of testicular spermatozoa pre‐varicocelectomy. Within the group of men who were negative for testicular spermatozoa a cut‐off value of TTA equal to 28 TPG U μg−1 protein (pre‐varicocelectomy) had a 84.2 % diagnostic accuracy to recognize the men who would become positive for either ejaculated or testicular spermatozoa post‐varicocelectomy. Testicular spermatozoa can be found in 40% of NOA men with left varicocele. Ooplasmic injections with frozen/thawed testicular spermatozoa have a role in the therapeutic management of non‐obstructive azoospermia associated with varicocele. Pre‐varicocelectomy, a TTA cut‐off value equal to 39 TPG U μg−1 protein has a 90.2% diagnostic accuracy to indicate the men positive/negative for testicular spermatozoa. In addition, pre‐varicocelectomy, a cut‐off value equal to 28 TPG U μg−1 protein has a 84.2% diagnostic accuracy to identify those men with varicoceles without testicular spermatozoa, who will become positive/negative for spermatozoa (either ejaculated or testicular) post‐varicocelectomy.

Effects of phosphodiesterase‐5 inhibitor vardenafil on testicular androgen‐binding protein secretion, the maintenance of foci of advanced spermatogenesis and the sperm fertilising capacity in azoospermic men

We evaluated the effects of vardenafil on testicular androgen‐binding protein secretion (ABP). Bilaterally obstructed azoospermic (OA)‐men (n = 19) (group A) underwent unilateral testicular biopsy. A group of nonobstructed azoospermic (NOA)‐men (n = 68) (group B) underwent bilateral testicular biopsy. ABP secretion in vitro by testicular tissue was assessed in each participant of every group. In addition, intracytoplasmic sperm injection (ICSI) cycles were performed in several couples of group A or group B using frozen/thawed spermatozoa from the biopsy material. Ten OA‐men (group A1), 14 NOA‐men (group B1), and nine different NOA‐men (group B2) had been positive for spermatozoa in the biopsy but pregnancies were not achieved in the respective female partners. Men of groups A1, B1 and B2 were treated with vardenafil, vardenafil and l‐carnitine respectively. Then, the men of groups A1, B1 and B2 underwent a second testicular (unilateral) biopsy. Within the group A1 and within the group B1, ABP secretion rate was significantly larger after vardenafil treatment than prior to vardenafil treatment. In addition, fertilisation rates in ICSI cycles within groups A1 or B1 were not affected by vardenafil administration. Vardenafil administration in NOA‐men increased ABP secretion and did not affect detrimentally the presence of testicular foci of advanced spermatogenesis.

Fibroepithelial Polyp of Distal Ureter with Periodic Prolapse into Bladder

Ureteric fibroepithelial polyp is a rare disease; it is of mesodermal origin and exhibits benign characteristics. Hydronephrosis occurs in rare cases, and it is generally accepted that it may result in an obstruction without causing alterations of renal function. In many cases it is difficult to differentiate from transitional cell carcinomas. Nowadays, endoscopic evaluation is the means of treatment and management. In our case study we report a patient with a long fibroepithelial polyp of the distal ureter prolapsing into the bladder in a periodic pattern. Cystoscopy revealed that movement of the polyp was moving forward and backward in the right ureteric orifice. Cold-cut biopsy established the diagnosis. The patient underwent ureteroscopic excision and remains asymptomatic a year later.

In vitro spermatogenesis as a method to bypass pre‐meiotic or post‐meiotic barriers blocking the spermatogenetic process: genetic and epigenetic implications in assisted reproductive technology

Pregnancies achieved by assisted reproduction technologies and particularly by ooplasmic injections of either in vivo or in vitro generated immature male germ cells are susceptible to genetic risks inherent to the male population treated with assisted reproduction and additional risks inherent to these innovative procedures. The documented, as well as the theoretical risks, are discussed in this review. These risks represent mainly the consequences of genetic abnormalities underlying male infertility and may become stimulators for the development of novel approaches and applications in the treatment of infertility. Recent data suggest that techniques employed for in vitro spermatogenesis, male somatic cell haploidisation, stem cell differentiation in vitro and assisted reproductive technology may also affect the epigenetic characteristics of the male gamete, the female gamete, or may have an impact on early embryogenesis. They may be also associated with an increased risk for genomic imprinting abnormalities. Production of haploid male gametes in vitro may not allow the male gamete to undergo all the genetic and epigenetic alterations that the male gamete normally undergoes during in vivo spermatogenesis.

The role of apparent diffusion coefficient values in detecting testicular intraepithelial neoplasia: Preliminary results

INTRODUCTION The aim of this study is to improve detection of testicular intraepithelial neoplasia (TIN) by measurement of apparent diffusion coefficient (ADC) values. MATERIALS AND METHODS Fifty-six MRI examinations of the scrotum, including 26 histologically proven testicular germ cell neoplasms were retrospectively evaluated. DWI was performed using a single shot, multi-slice spin-echo planar diffusion pulse sequence and b-values of 0 and 900 s mm(-2). ADC measurements were classified into three groups according to their location: group 1 (n=19), non-tumoral part, adjacent to testicular carcinoma, where the possible location of TIN was; group 2 (n=26), testicular carcinoma; and group 3 (n=60), normal testicular parenchyma. Analysis of variance (ANOVA) followed by post hoc analysis (Dunnett T3) was used for statistical purposes. RESULTS The mean±s.d. of ADC values (×10(-3) mm(2)/s) of different groups were: group 1, 1.08±0.20; group 2, 0.72±0.27; and group 3, 1.11±0.14. ANOVA revealed differences of mean ADC between groups (F=38.859, P<0.001). Post hoc analysis showed differences between groups 2 and 3 (P<0.001), groups 2 and 1 (P<0.001), but not between groups 3 and 1 (P=0.87). CONCLUSIONS Based on our preliminary results, ADC values do not provide a reliable differentiation between TIN and testicular carcinoma or normal testicular parenchyma.