Elisabeth Pinart

Bio: Elisabeth Pinart is an academic researcher from University of Girona. The author has contributed to research in topics: Sperm & Sperm motility. The author has an hindex of 21, co-authored 54 publications receiving 1226 citations.

Effects of cryopreservation on semen quality and the expression of sperm membrane hexose transporters in the spermatozoa of Iberian pigs

Abstract: This study evaluated the effects of cooling, freezing and thawing on the plasma membrane integrity, kinetics and expression of two sugar transporters glucose transporter-3 and -5 (GLUT-3 and GLUT-5) in spermatozoa from Iberian boars. Semen samples were collected twice weekly from eight young, fertile Iberian boars of the 'Entrepelado' and 'Lampino' breeds. The samples were suspended in a commercial extender and refrigerated to 17 degrees C for transport to the laboratory (step A), where they were further extended with a lactose-egg yolk-based extender and chilled to 5 degrees C (step B) prior to freezing in the presence of glycerol (3%). Spermatozoa were assessed for plasma membrane integrity and sperm motility at each of the steps, including post-thaw (step C). Aliquots were also prepared for immunocytochemical localisation of the sugar transporters (fixed and thin smears for transmission and scanning electron microscopy levels respectively) and for SDS-PAGE electrophoresis and subsequent western blotting, using the same antibodies (rabbit anti-GLUT-3 and anti-GLUT-5 polyclonal antibodies). The results showed lower percentages of progressively motile spermatozoa at step C in both breeds, while the percentage of live spermatozoa was significantly lower only in the 'Entrepelado' breed. The results obtained from electron microscopy clearly showed that Iberian boar spermatozoa expressed the hexose transporters, GLUT-3 and GLUT-5. The pattern of expression, in terms of location and concentration, was characteristic in each case but, in the case of isoform GLUT-5, it remained constant during the different steps of freezing-thawing protocol. These results indicate that cryopreservation affects the status of sperm cells of Iberian boars by altering the distribution of some membrane receptors and decreasing the percentage values of parameters linked to sperm quality.

Proliferation and functional maturation of Sertoli cells, and their relevance to disorders of testis function in adulthood

Abstract: Disorders of testicular function may have their origins in fetal or early life as a result of abnormal development or proliferation of Sertoli cells. Failure of Sertoli cells to mature, with consequent inability to express functions capable of supporting spermatogenesis, is a prime example. In a similar way, failure of Sertoli cells to proliferate normally at the appropriate period in life will result in reduced production of spermatozoa in adulthood. This review focuses on the control of proliferation of Sertoli cells and functional maturation, and is motivated by concerns about 'testicular dysgenesis syndrome' in humans, a collection of common disorders (testicular germ-cell cancer, cryptorchidism, hypospadias and low sperm counts) which are hypothesized to have a common origin in fetal life and to reflect abnormal function of Sertoli (and Leydig) cells. The timing of proliferation of Sertoli cells in different species is reviewed, and the factors that govern the conversion of an immature, proliferating Sertoli cell to a mature, non-proliferating cell are discussed. Protein markers of maturity and immaturity of Sertoli cells in various species are reviewed and their usefulness in studies of human testicular pathology are discussed. These markers include anti-Mullerian hormone, aromatase, cytokeratin-18, GATA-1, laminin alpha5, M2A antigen, p27(kip1), sulphated glycoprotein 2, androgen receptor and Wilms' tumour gene. A scheme is presented for characterization of Sertoli-cell only tubules in the adult testis according to whether or not there is inherent failure of maturation of Sertoli cells or in which the Sertoli cells have matured but there is absence, or acquired loss, of germ cells. Functional 'de-differentiation' of Sertoli cells is considered. It is concluded that there is considerable evidence to indicate that disorders of maturation of Sertoli cells may be a common underlying cause of human male reproductive disorders that manifest at various life stages. This recognition emphasizes the important role that animal models must play to enable identification of the mechanisms via which failure of proliferation and maturation of Sertoli cells can arise, as this failure probably occurs in fetal life.

Regulation of the fructose transporter GLUT5 in health and disease.

Abstract: Fructose is now such an important component of human diets that increasing attention is being focused on the fructose transporter GLUT5. In this review, we describe the regulation of GLUT5 not only in the intestine and testis, where it was first discovered, but also in the kidney, skeletal muscle, fat tissue, and brain where increasing numbers of cell types have been found to have GLUT5. GLUT5 expression levels and fructose uptake rates are also significantly affected by diabetes, hypertension, obesity, and inflammation and seem to be induced during carcinogenesis, particularly in the mammary glands. We end by highlighting research areas that should yield information needed to better understand the role of GLUT5 during normal development, metabolic disturbances, and cancer.

New insights into epididymal function in relation to sperm maturation.

Abstract: Testicular spermatozoa acquire fertility only after 1 or 2 weeks of transit through the epididymis. At the end of this several meters long epididymal tubule, the male gamete is able to move, capacitate, migrate through the female tract, bind to the egg membrane and fuse to the oocyte to result in a viable embryo. All these sperm properties are acquired after sequential modifications occurring either at the level of the spermatozoon or in the epididymal surroundings. Over the last few decades, significant increases in the understanding of the composition of the male gamete and its surroundings have resulted from the use of new techniques such as genome sequencing, proteomics combined with high-sensitivity mass spectrometry, and gene-knockout approaches. This review reports and discusses the most relevant new results obtained in different species regarding the various cellular processes occurring at the sperm level, in particular, those related to the development of motility and egg binding during epididymal transit.

Regulation of Sertoli Cell Number and Activity by Follicle-Stimulating Hormone and Androgen during Postnatal Development in the Mouse

Abstract: The roles of FSH and androgen in the postnatal development of Sertoli cell number and function have been investigated using mice that lack FSH (FSHbetaKO), FSH-receptors (FSHRKO), or androgen receptors (Tfm). At birth and d 5, Sertoli cell number was normal in FSHRKO and FSHbetaKO mice, but was significantly reduced on d 20 and in adulthood. In contrast, Sertoli cell number was reduced at birth in Tfm mice and remained significantly less than normal up to adulthood. Sertoli cell activity was determined through measurement of 11 different mRNA transcript levels. From birth to adulthood, the expression of most transcripts increased, with a significant rise occurring between d 5 and 10. In animals lacking FSH stimulation, mRNA expression (measured per Sertoli cell) was largely normal on d 5, but was reduced in seven transcripts on d 20 and in five transcripts at adulthood. In Tfm mice two transcripts showed reduced expression on d 5, and four were reduced on d 20, although expression in adult Tfm mice did not differ from that in normal cryptorchid controls. The results show that 1) testosterone, but not FSH, is required for Sertoli cell proliferation during fetal and early neonatal life; 2) FSH and testosterone both regulate the late stages of Sertoli cell proliferation; 3) FSH has a general trophic effect on Sertoli cell activity in the pubertal and adult mouse; and 4) androgens are required for specific transcript expression during prepubertal development. Specific effects of androgens were not seen in the adult, although these may be masked by the effects of cryptorchidism.