Thamara Viloria

Time-dependent O2 consumption patterns determined optimal time ranges for selecting viable human embryos

OBJECTIVE To evaluate correlations between metabolic activity and implantation potential of transferred embryos in a study based on oxygen (O(2)) consumption (OC) measurements, because O(2) uptake is directly related to the capacity of an embryo to produce energy via adenosine triphosphate. DESIGN Retrospective cohort study. SETTING Infertility institute. PATIENT(S) Five hundred seventy-five injected oocytes in 56 first oocyte donation cycles with embryo transfer on day 3. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) We analyzed embryo destination viability and implantation depending on the embryo OC rate obtained from 47,741 measurements (up to 85 measurements per embryo, 2-3 measurements per hour). OC patterns were analyzed in relation to the time elapsed from sperm microinjection, to the final destination of the embryos (transferred, frozen, or discarded), to ongoing pregnancy, and by successful implantation. RESULT(S) OC was found to decrease during embryonic development. OC patterns from 52 hours onward showed the strongest correlation with implantation success. Regarding embryo destination, the same patterns were observed. CONCLUSION(S) OC from individual embryos revealed significant differences, mainly close to the time of transfer, when OC pattern was associated with successful implantation. Therefore, measuring the OC pattern of human embryos culture up to 72 hours could be used to select the embryo with best developmental potential.

Reduced oxygen tension improves embryo quality but not clinical pregnancy rates: a randomized clinical study into ovum donation cycles.

OBJECTIVE To investigate the effect of low O2 tension during in vitro culture in terms of ongoing pregnancy rates in ovum donation cycles. DESIGN Randomized trial. SETTING Private university-affiliated IVF center, university-based hospital. PATIENT(S) A total of 1,125 cycles of ovum donation. INTERVENTION(S) Embryo culture in an atmosphere of 5.5% CO2, 6% O2, and 88.5% N2 versus a dual-gas system of 5.5% CO2 in air. MAIN OUTCOME MEASURE(S) Ongoing clinical pregnancy rates per intention-to-treat (ITT) patients. RESULT(S) The use of low O2 tension achieved a 41.3% ongoing pregnancy rate per ITT compared with a 40.8% rate obtained for 5% CO2 in air. The mean number of blastomeres and the percentage of top-quality embryos were significantly higher after lower O2 concentration during in vitro culture (7.1 ± 3.6 and 28.6% vs. 7.3 ± 8.4 and 32.1%, respectively). CONCLUSION(S) In the ovum donation cycles undergoing day-3 embryo transfers, the use of low O2 tension did not improve ongoing pregnancy rates per cycle and per transfer. However, it benefited embryo quality, demonstrating the potential negative impact of high O2 tension on the in vitro embryo development.

Cigarette smoking affects specific sperm oxidative defenses but does not cause oxidative DNA damage in infertile men

OBJECTIVE To evaluate the effects of tobacco consumption on the oxidative defenses of sperm, the glutathione system (GS), and sperm DNA oxidation. DESIGN Double-blind experimental study. SETTING Andrology laboratory in a university-affiliated private setting. PATIENT(S) One hundred seventeen semen samples from infertile males. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) (a) sperm GS enzymatic activity with respect to glutathione peroxidase isoforms GPx-1 and GPx-4, glutathione reductase (GR), and cellular glutathione (GSH) content (n = 29); (b) GPx-1, GPx-4, and GR mRNA expression analysis (n = 33); (c) oxidative DNA damage quantification using OXIDNA assay kit (n = 55). Two groups were established: nonsmoking and smoking males. The t tests were employed to detect significant differences between groups. RESULT(S) We identified a significant decrease in sperm GPx-4 activity but not in GPx-1 and GSH activity in smokers compared with nonsmokers. A significant decrease was also observed in GPx-1, GPx-4, and GR mRNA expression in the former group. Interestingly, we did not observe any significant variation in the percentage of cells with oxidative damage of the DNA or in the average level of oxidation of affected cells with respect to the smoking condition of the male. CONCLUSION(S) We demonstrate that smoking has a negative impact on intracellular antioxidant enzymes but that effect does not increase oxidative DNA damage. Thus, the effects of reduced oxidative defenses in sperm as a result of cigarette smoking are yet to be elucidated.

Report of results obtained in 2,934 women using donor sperm: donor insemination versus in vitro fertilization according to indication

OBJECTIVE To demonstrate that the use of donor sperm leads to varying outcome rates and that its use has evolved. DESIGN Retrospective observational cohort study. SETTING University-affiliated private IVF setting. PATIENT(S) Women (2,934) undergoing donor insemination (DI) or IVF with donor sperm (IVF-D). INTERVENTION(S) None. MAIN OUTCOME MEASUREMENT(S) We evaluated the distribution of the clinical indications for the use of donated sperm, studying the reproductive outcome. RESULT(S) A total of 1,663 DI (57%) and 1,271 IVF-D (43%) were performed. There were significant differences in the indications for the use of donated sperm (DI vs. IVF-D). Regarding pregnancy rates (PR), cases of nonobstructive azoospermia presented the highest rate (29.1%), whereas cases of intracytoplasmic sperm injection (ICSI) failures and single women showed rates of 27.6% and 22.6%, respectively. Meanwhile, patients with ICSI failures achieved the highest PRs in IVF cycles (48.7%), whereas nonobstructive azoospermia and single women showed rates of 42.0% and 38.2%, respectively. There have been significant increases in the use of donated sperm in single women. CONCLUSION(S) Single women, which also represented the oldest group, show a lower probability of achieving pregnancy, and thus represent a subfertile population. Associated factors could include advanced maternal age.

Culture Systems for the Human Embryo

Human-assisted reproduction techniques (ART) have profoundly changed over the last decades. It is now a scientific field where novel research works continuously emerge and it is becoming an exciting area to investigate and work in. Since the first in vitro fertilization (IVF) birth, novel techniques and procedures, such as intracytoplasmic sperm injection (ICSI), sperm isolation, thawed embryo transfer, preimplantation genetic diagnosis (PGD), oocyte vitrification, time-lapse embryo assessment, have improved from the beginning. However, optimization of in-vitro culture conditions and the selection of the embryos aimed at improving pregnancy rates are important and fundamental components in an ART program.

Processing Sperm Samples in HIV-Positive Patients

Human immunodeficiency virus is an important public health problem; about 40 million people around the world are actually infected with HIV type 1 virus. Furthermore, prolonged survival of patients under highly active antiretroviral therapy has given rise to a new demand from SDC couples who wish to have children. HIV serodiscordant couples with the male infected wish to make use of assisted reproduction techniques in combination with semen washing in order to decrease the risk of transmission to the partner or to the newborn. Thus it is essential to test the effectiveness of techniques aimed at reducing HIV and HCV loads in infected semen using molecular biology tests. Nevertheless, its efficiency is not absolute, and it remains unclear if the efficacy of sperm wash depends on the viral load of the ejaculate, in the laboratory handling or both. Our aim with this chapter is to compile the available information about sperm washes and assisted reproduction treatments with sperm samples obtained from serodiscordant males for HIV to describe the current possibilities of these males.

Biochemical markers of male infertility: the key role of DNA damage

One product resulting from free radical damage is DNA hydroxylation, also known as DNA oxidation and DNA fragmentation. DNA oxidative damage is indicative of a number of conditions involving the generation of oxygen free radicals. This damage could be the primary source of DNA fragmentation. We will overview some of the conditions in which this phenomenon is present and we will focus the major part of this review describing the methods to study DNA damage and the implications of this phenomenon in male infertility, most of them reflected in the IVF outcome. Finally, we will describe which could be factors related with DNA damage, including chemicals, radiation, diseases and normal metabolic activity.