Júlia Silva

Effect of insulin deprivation on metabolism and metabolism-associated gene transcript levels of in vitro cultured human Sertoli cells.

BACKGROUND Sertoli cells metabolize glucose producing lactate for developing germ cells. As insulin regulates glucose uptake and its disturbance/insensitivity is associated with diabetes mellitus, we aimed to determine the effect of insulin deprivation in human Sertoli cell (hSC) metabolism and metabolism-associated gene expression. METHODS hSC-enriched primary cultures were maintained in the absence/presence of insulin and metabolite variations were determined by (1)H-NMR. mRNA expression levels of glucose transporters (GLUT1, GLUT3), lactate dehydrogenase (LDHA) and monocarboxylate transporter (MCT4) were determined by RT-PCR. RESULTS Insulin deprivation resulted in decreased lactate production and in decrease of glucose consumption that was completely reverted after 6h. Cells of both groups consumed similar amounts of glucose. In insulin-deprived cells, transcript levels of genes associated to lactate metabolism (LDHA and MCT4) were decreased. Transcript levels of genes involved in glucose uptake exhibited a divergent variation: GLUT3 levels were decreased while GLUT1 levels increased. Insulin-deprived hSCs presented: 1) altered glucose consumption and lactate secretion; 2) altered expression of metabolism-associated genes involved in lactate production and export; 3) an adaptation of glucose uptake by modulating the expression of GLUT1 and GLUT3. GENERAL SIGNIFICANCE This is the first report regarding the effect of insulin-deprivation on hSC metabolism.

Influence of 5α-dihydrotestosterone and 17β-estradiol on human Sertoli cells metabolism

Sertoli cells metabolize glucose, converting it to lactate that is used by developing germ cells for their energy metabolism. Androgens and oestrogens have metabolic roles that reach far beyond reproductive processes. So, the main purpose of this study was to examine the effect of sex steroid hormones on metabolite secretion/consumption in human Sertoli cells. Human Sertoli cell-enriched primary cultures were maintained in a defined medium for 50 h and glucose, pyruvate, lactate and alanine variations were determined using (1) H-NMR spectra analysis, in the absence or presence of 100 nm 17β-estradiol (E(2) ) or 100 nm 5α-dihydrotestosterone (DHT). The mRNA expression levels of glucose transporters, lactate dehydrogenase and monocarboxylate transporters were also determined using semi-quantitative RT-PCR. Cells cultured in the absence (control) or presence of E(2) consumed the same amounts of glucose at similar rates during the 50 h. During the first 15 h of treatment with DHT, glucose consumption and glucose consumption rate were significantly higher. Nevertheless, DHT-treated cells secreted a significantly lower amount of lactate than control and E(2) -treated cells. Such a decrease was concomitant with a significant decrease in lactate dehydrogenase A mRNA levels after 50 h treatment in DHT-treated groups. Finally, alanine production was significantly increased in E(2) -treated cells after 25 h treatment, which indicated a lower redox/higher oxidative state for the cells on those conditions. These results support the existence of a relationship between sex steroid hormones action and energy metabolism, providing the first assessment of androgens and oestrogens as metabolic modulators of human Sertoli cells.

Treatment by testicular sperm extraction and intracytoplasmic sperm injection of 65 azoospermic patients with non‐mosaic Klinefelter syndrome with birth of 17 healthy children

The aim of this work was to present the clinical and embryological outcomes of 65 azoospermic patients with non‐mosaic Klinefelter syndrome (KS), treated by testicular sperm extraction (TESE), followed by intracytoplasmic sperm injection (ICSI), either with fresh or cryopreserved testicular spermatozoa. In total, spermatozoa were recovered in 25/65 (38.5%) of the cases. Of the 48 patients who choose to perform TESE followed by ICSI using fresh testicular spermatozoa (treatment TESE), spermatozoa was recovered in 19 patients (40%), with birth of 12 newborn. Of the 17 patients who choose to perform TESE followed by testicular sperm cryopreservation, spermatozoa were recovered in six patients (35%), with birth of one child. Of the patients who performed treatment TESE, nine went for a new cycle using cryopreserved spermatozoa. Of these, five patients had a previous failed treatment cycle (two patients, three newborn) and four with a previous success went for a new cycle (one patient, one newborn). Overall, the embryological and clinical rates were as follows: 52% of fertilization, 41% of blastocyst, 27% of implantation, 39% of live birth delivery and 47% of newborn. Of the 16 clinical pregnancies, 14 had a successful delivery (12 girls and 5 boys). The 17 newborns had a mean gestation time of 37.2 weeks (35.3% pre‐term) and a mean newborn weight of 2781.3 g (37.5% low weight). Comparisons between cycles with fresh and frozen‐thaw spermatozoa revealed higher fertilization and clinical pregnancy rates with fresh spermatozoa, with no differences regarding implantation or newborn rates. Of the 17 newborns, no abnormal karyotypes (n = 3) or numerical abnormalities in chromosomes 13, 18, 21, X and Y (n = 14) as evaluated by Multiplex Ligation–dependent Probe Amplification were observed. In conclusion, this study presents further data that reassures that men with KS have no increased risk of transmitting their genetic problem to the offspring.

Immunohystochemical analysis of CFTR in normal and disrupted spermatogenesis

Cystic fibrosis is the most frequent autosomal recessive disease in the Caucasian population, with an incidence of 1:2500 newborn and a frequency of 1:25. The associated gene is Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and it encodes the CFTR protein that functions as a chloride (Cl−) channel. It is found in the apical membrane of exocrine epithelial cells, responsible for the regulation of the movement of water and solutes through biological membranes. To our knowledge, there are no studies on protein localization in the different cell types of the seminiferous epithelium with different pathologies. The aim of the present study was to analyze the expression of the CFTR protein in the human seminiferous epithelium of infertile males with different pathologies. CFTR protein expression was studied by immunohistochemistry in paraffin sections of testicular biopsies of six infertile men: Sertoli cell only syndrome, maturation arrest, secondary obstructive azoospermia, primary obstructive azoospermia due to congenital bilateral absence of the vas deferens (CBAVD), severe oligozoospermia, and retrograde ejaculation. All cell types of the seminiferous epithelium were studied: Sertoli cells, spermatogonia, primary spermatocytes at the leptotene/zygotene and at the pachytene stages, secondary spermatocytes, round, elongating and elongated spermatids, and spermatozoa. With the exception of sperm, all cells were labeled in the cytoplasm and in the cytoplasmic membrane. In the patient with CBAVD labeling was light at the cell membrane and absent in the cytoplasm of Sertoli cells and diploid germ cells. Generally, labeling was stronger after the diploid stage, which is probably related to cell volume reduction during spermiogenesis. The results obtained also suggest that the CFTR protein may impact CBAVD spermatogenesis and other pathologies.

Caspase-3 detection in human testicular spermatozoa from azoospermic and non-azoospermic patients

The apoptotic mechanisms underlying spermatogenesis in testis are poorly understood. In the present study, the rates of testicular spermatozoa with active caspase-3 were quantified in testicular samples with normal and impaired spermatogenesis. Testicular spermatozoa were collected from 18 men after testicular biopsy during assisted reproductive treatments: five presented oligozoospermia, four congenital bilateral absence of the vas deferens (CBAVD), five secondary obstructive azoospermia (sOAZ) and four hypospermatogenesis. Ejaculated samples were derived from six normozoospermic patients. Testicular spermatozoa were analysed using a fluorescence microscope and differences among groups were calculated using regression logistic models. Total rates of spermatozoa with active caspase-3 were significantly higher in sOAZ (78.6±13.9), followed by hypospermatogenesis (70.8±5.8), CBAVD (55.9±25.5), oligozoospermia (31.7±31.0) and normozoospermia (20.4±15.5). Distinct patterns of active caspase-3 were observed in testicular spermatozoa compartments: midpiece, equatorial region, acrosomal vesicle region, nucleus and cytoplasm. Hypospermatogenesis showed active caspase-3 mainly in the midpiece. In CBAVD, sOAZ and oligozoospermia, active caspase-3 was mainly in the nucleus, although no differences were found between oligozoospermia and hypospermatogenesis. In sOAZ, active caspase-3 in the spermatozoa nucleus was 1.89-fold higher than in CBAVD. Results suggest that tubular obstruction may induce nuclear lesions and that disrupted spermatozoa production observed in cases of hypospermatogenesis might be associated with mitochondrial lesions.

Embryological, clinical and ultrastructural study of human oocytes presenting indented zona pellucida

Human oocyte dysmorphisms attain a large proportion of retrieved oocytes from assisted reproductive technology (ART) treatment cycles. Extracytoplasmic defects involve abnormal morphology of the zona pellucida (ZP), perivitelline space and first polar body. The aim of the present study was to describe a novel dysmorphism affecting the ZP, indented ZP. We also evaluated the clinical, embryological and ultrastructural features of these cases. We evaluated all ART treatment cycles during 7 consecutive years and found 13 treatment cycles (six patients) with all oocytes presenting an indented ZP. In addition, these oocytes presented total or partial absence of the perivitelline space, absence of resistance to ZP and oolemma penetration during microinjection, and low ooplasm viscosity during aspiration. This novel described dysmorphism was recurrent and attained all oocytes in three cases that had more than one treatment cycle. When compared with controls, data showed significant low oocyte maturity (42% versus 81.6%) and high cycle cancellation (30.8% versus 8.5%) rates, normal degeneration (3.4% versus 6.3%) and fertilization rates (69% versus 69.5%), and low pregnancy (15.4% versus 33.3%) and live-birth delivery (7.7% versus 27.7%) rates per cycle. Ultrastructure analysis revealed a zona pellucida structure with large empty electrolucent regions, an outer ZP layer with an indented surface with protuberances and a thick inner ZP that obliterated the perivitelline space. There was evidence of exocytosis of ZP material by the oocyte. In conclusion, oocytes with this novel described dysmorphism (indented ZP) are associated with low maturity, pregnancy and live-birth delivery rates.

Pioglitazone increases the glycolytic efficiency of human Sertoli cells with possible implications for spermatogenesis

Pioglitazone is a synthetic agonist for the nuclear receptor peroxisome proliferator-activated receptor γ used to treat type 2 diabetes mellitus. Recently we reported that antidiabetic drugs regulate the nutritional support of spermatogenesis by Sertoli cells. Herein, we investigate the effects of pioglitazone on human Sertoli cells metabolism. Human Sertoli cells were cultured in the presence of pioglitazone (1, 10, 100μM). Protein levels of phosphofructokinase 1, lactate dehydrogenase, hexokinase, glucose transporters (GLUT1, GLUT2, GLUT3), monocarboxylate transporter 4 and oxidative phosphorylation complexes were determined by Western blot. Lactate dehydrogenase and alanine aminotransferase activity were assessed and metabolite production and consumption determined by proton nuclear magnetic resonance. Mitochondrial membrane potential was also determined. Glucose consumption more than doubled in human Sertoli cells stimulated with pioglitazone 100μM. Mitochondrial complex II protein levels increased 50% with exposure to pioglitazone (100μM) in human Sertoli cells, though mitochondrial membrane potential was decreased by 32%. The pharmacological concentration of pioglitazone (10μM) almost doubled lactate production and established crucial correlations among key intervenient of glycolysis. Moreover, in the same concentration, alanine aminotransferase decreased more than 80%. Our results suggest that pioglitazone (10μM) increases the efficiency of the glycolytic flux and lactate production by human Sertoli cells, which is essential to sustain and preserve the spermatogenic event. Thus, pioglitazone may improve male fertility and thus, be considered a suitable antidiabetic drug for men in reproductive age.

Effect of in vitro exposure to lead chloride on semen quality and sperm DNA fragmentation.

Exposure to lead may cause changes in the male reproductive system. We evaluated the effect of lead chloride (PbCl2) in vitro on semen quality from 31 individuals. Samples were incubated at room temperature for two exposure times (4 h and 8 h) and with two concentrations of PbCl2 (15 μg/ml or 30 μg/ml). Results showed that PbCl2 significantly inhibited rapid progressive motility and caused an increase in the percentage of tail anomalies in both times and concentrations assessed, as well as a decrease in vitality in the group exposed to 30 μg/ml PbCl2. A significant increase in immotile sperm was also observed between the group control and the groups submitted to lead. Total motility and DNA fragmentation also showed a significant decrease and increase, respectively, after 4 h of incubation in the group exposed to 30 μg/ml and in both groups after 8 h of incubation. In conclusion, PbCl2 affected sperm parameters and DNA integrity, which are essential for male fertility.

The mutational spectrum of WT1 in male infertility.

PURPOSE We evaluated the impact of WT1 mutations in isolated severe spermatogenic impairment in a population of European ancestry. WT1 was first identified as the gene responsible for Wilms tumor. It was later associated with a plethora of clinical phenotypes often accompanied by urogenital defects and male infertility. The recent finding of WT1 missense mutations in Chinese azoospermic males without major gonadal malformations broadened the phenotypic spectrum of WT1 defects and motivated this study. MATERIALS AND METHODS We analyzed the WT1 coding region in a cohort of 194 Portuguese patients with nonobstructive azoospermia and in 188 with severe oligozoospermia with increased depth for the exons encoding the regulatory region of the protein. We also analyzed a group of 31 infertile males with a clinical history of unilateral or bilateral cryptorchidism and 1 patient with anorchia. RESULTS We found 2 WT1 missense substitutions at higher frequency in patients than in controls. 1) A novel variant in exon 1 (p.Pro130Leu) that disrupted a mammalian specific polyproline stretch in the self-association domain was more frequent in azoospermia cases (0.27% vs 0.13%, p = 0.549). 2) A rare variant in a conserved residue in close proximity to the first zinc finger (pCys350Arg) was more frequent in severe oligozoospermia cases (0.80% vs 0.13%, p = 0.113). CONCLUSIONS Results suggest a role for rare WT1 damaging variants in severe spermatogenic failure in populations of European ancestry. Large multicenter studies are needed to fully assess the contribution of WT1 genetic alterations to male infertility in the absence of other disease phenotypes.

Biomarkers Expression in Human Seminiferous Epithelium

Spermatogenesis is a complex process of cell proliferation, meiosis and differentiation [1, 2]. In order to determine the genetic mechanisms that control this process we need to develop adequate methodologies for the purification of stage-specific germ cells. In this study we aim to evaluate four markers (c-kit, oct-4, Integrin α6 and Integrin β 1), used to isolate spermatogonial stem cells in mammals, as possible markers to isolate/sort testicular adult stem and progenitor cells in humans.