Optimizing the culture environment and embryo manipulation to help maintain embryo developmental potential

Abstract

With increased use of comprehensive chromosome screening (CCS), the question remains as to why some practices do not experience the same high levels of clinical success after implementation of the approach. Indeed, the debate surrounding the efficacy and usefulness of blastocyst biopsy and CCS continues. Importantly, several variables impact the success of an assisted reproductive technology cycle. Transfer of a euploid embryo is but one factor in an intricate system that requires numerous steps to occur successfully. Certainly, the culture environment and the manipulations of the embryo during its time in the laboratory can impact its reproductive potential. Environmental stressors ranging from culture media to culture conditions and even culture platform can impact biochemical, metabolic, and epigenetic patterns that can affect the developing cell independent of chromosome number. Furthermore, accompanying procedures, such as biopsy and vitrification, are complex and, when performed improperly, can negatively impact embryo quality. These are areas that likely still carry room for improvement within the IVF laboratory.

Humid versus dry incubator: a prospective, randomized, controlled trial

“…The incubator's environment, including the gas phase, recovery time, pH, and humidity, can dramatically influence its performance (3,6,8). There is no evidence to support the superiority of any of the available culture systems, including the time-lapse system (21,22).…”

“…Optimal pH levels, temperature, air quality, osmolality, and humidity should be maintained in embryo incubators (4)(5)(6)(7). Toward that end, incubators have undergone several improvements, with designs varying from the conventional CO 2 to time-lapse cinematography, including triple gas (low oxygen) and benchtop models (8).…”

Assessment of ‘one-step’ versus ‘sequential’ embryo culture conditions through embryonic genome methylation and hydroxymethylation changes

“…An additional advantage is that they are compatible with uninterrupted culture associated with the use of time-lapse technology. However, it remains impossible to this day to say which approach is superior (Mantikou et al ., 2013; Swain et al ., 2016), especially since studies in the human are made difficult by numerous confounding effects. Studies on animal models have shown that the environment surrounding oogenesis and the first steps of embryonic development influences the phenotype and can have effects during the animal's whole life (Fleming et al ., 2015), thus extending the concept of Developmental Origin of Health and Diseases (DOHaD) to the periconceptional period.…”

A Comparison of Embryonic Development and Clinical Outcomes between In vitro Oocytes Maturation Using Micro-Vibration System and In vivo Oocytes Maturation in Polycystic Ovarian Syndrome Patients

“…A dynamic culture system that imitates the in vivo physical environment has a beneficial effect on mammalian and human embryo development. It can improve implantation and pregnancy rates in humans [16]. Mechanical micro-vibration, one of the dynamic culture systems, can enhance the cytoplasmic maturation of porcine immature oocytes.…”