Respiration measurements of human oocytes correlate with oocyte competence

Abstract

Mitochondria are key to cellular energy generation, homeostasis and cell life; function actively during oocyte maturation, fertilization and embryo development through ATP production. Measuring ATP content necessitates oocyte destruction, but measuring activity through oxygen consumption is non-invasive. Retrospective. Respiration rates (RR; nL/H) of single oocytes from ICSI (D 0; GV and M I) and insemination cycles (D1; GV, M I, M II) were measured non-invasively (EmbryoScope-Unisense, Aarhus, Denmark) at 15–60 minutes over 3–5 hours, for base respiration rate (BRR). Oocytes were cultured overnight (18 hours) to assess developmental and maturational competence (maturation, arrest, attresia) which was correlated with BRR. BRR was correlated with infertility diagnosis, days of FSH administration, total number of oocytes retrieved and fertilization rates in non-ICSI cycles. BRR significantly correlated with oocyte developmental and cellular competence, reduced rates in those that became attretic (0.0019) and high in oocytes that were abnormal (1.24). Intermediate rates were obtained for arrested or matured oocytes. BRR of oocytes derived from failed fertilization with no male factor had significantly decreased rates. BRR of oocytes from patients with decreased ovarian reserve, PCOS and repeat pregnancy loss was significantly reduced. Oocytes derived from patients with <8 days of FSH and with >25 oocytes retrieved had reduced BRR. BRR correlated with fertilization rates, developmental competence, infertility etiology and factors affecting ovarian stimulation. Since our technique is non-invasive and BRR can be obtained expeditiously, respiration rates of oocytes may provide a feasible selection technique for enhanced development and clinical outcome.