Worldwide obesity rates have nearly doubled since 1980 and currently over 10% of the population is obese. In 2008, over 1.4 billion adults aged 20 years and older had a body mass index or BMI above a healthy weight and of these, over 200 million men and nearly 300 million women were obese. While obesity can have many ramifications upon adult life, one growing area of concern is that of reproductive capacity. Obesity affects male infertility by influencing the hypothalamic-pituitary-gonadal axis, thus causing detrimental effects upon spermatogenesis and subsequent fertility. In particular, evidence indicates that excess adipose tissue can alter the relative ratio of testosterone and oestrogen. Additional effects involve the homeostatic disruption of insulin, sex-hormone-binding-globulin, leptin and inhibin B, leading to diminished testosterone production and impairment to spermatogenesis. Aberrant spermatogenesis arising from obesity is associated with downstream changes in key semen parameters, defective sperm capacitation and binding, and deleterious effects on sperm chromatin structure. More recent investigations into trans-generational epigenetic inheritance further suggest that molecular changes in sperm that arise from obesity-related impaired spermatogenesis, such as modified sperm RNA levels, DNA methylation, protamination and histone acetylation, can impact upon the development of offspring. Here, we summarise our current understanding of how obesity exerts influence over spermatogenesis and subsequent fertility status, and make recommendations for future investigative research.

Successful pregnancy is dependent upon the implantation of a competent embryo into a receptive endometrium. Despite major advancement in our understanding of reproductive medicine over the last few decades, implantation failure still occurs in both normal pregnancies and those created artificially by assisted reproductive technology (ART). Consequently, there is significant interest in elucidating the etiology of implantation failure. The complex multistep process of implantation begins when the developing embryo first makes contact with the plasma membrane of epithelial cells within the uterine environment. However, although this biological interaction marks the beginning of a fundamental developmental process, our knowledge of the intricate physiological and molecular processes involved remains sparse. In this synopsis, we aim to provide an overview of our current understanding of the morphological changes which occur to the plasma membrane of the uterine endothelium, and the molecular mechanisms that control communication between the early embryo and the endometrium during implantation. A multitude of molecular factors have been implicated in this complex process, including endometrial integrins, extracellular matrix molecules, adhesion molecules, growth factors, and ion channels. We also explore the development of in vitro models for embryo implantation to help researchers investigate mechanisms which may underlie implantation failure. Understanding the precise molecular pathways associated with implantation failure could help us to generate new prognostic/diagnostic biomarkers, and may identify novel therapeutic targets.

This review discusses the current status of laser-assisted reproductive technologies in human infertility treatment. We highlight the benefits of laser technology in diagnostic and therapeutic treatments for subfertility and male-factor infertility, and current concern of this application in different clinical practice. ABSTRACTTo improve success rates, assisted reproductive technology (ART) procedures continually undergo optimization and enhancement such that the best quality gametes and embryos can be identified and manipulated, thus improving clinical outcomes. Laser technology is now being applied across ART to reduce procedure times and increase the consistency and reproducibility of traditional ART techniques such as assisted hatching, embryo biopsy, intracytoplasmic sperm injection cryopreservation and sperm immobilization/selection. This review examines the current status of cutting-edge laser-assisted reproductive technologies, investigates experimental techniques that are increasingly being applied clinically. It highlights the benefits of lasers as a powerful technology at the forefront of both diagnostic and therapeutic treatments for general subfertility and male-factor infertility. However, it is important to note that although lasers are becoming increasingly commonplace in ART units, there is comparatively little information in the existing literature pertaining to the potential negative effects that laser application might have on the developing human embryo, thus creating the need for further investigative research.