Long-Acting Depot Formulation of Luprolide Acetate as a Method of Hypothalamic Down Regulation for Controlled Ovarian Hyperstimulation and Oocyte Production in Macaca fascicularis1

Abstract

Reproductive function in some nonhuman primate species parallels that of the human. As a result, studies addressing aspects of reproductive function primarily involve the use of nonhuman primate models. The objective of the present study was to assess the efficiency of two hypothalamic down-regulation techniques combined with a single controlled ovarian hyperstimulation protocol for mature oocyte production in the cynomolgus macaque (Macaca fascicularis). Hypothalamic GnRH down regulation was first induced using the clinical long protocol of the short-acting GnRH-agonist luprolide acetate combined with controlled ovarian hyperstimulation and oocyte retrieval. Resulting oocyte yield and maturity with this regimen was insufficient for further evaluation of oocyte competency. Hypothalamic down regulation was induced in the second experiment using the long-acting depot formulation of luprolide acetate in conjunction with controlled ovarian hyperstimulation. This regimen allowed for the consistently efficient production of oocytes (15.5 oocytes per oocyte retrieval) and an oocyte maturity rate of 56%. Oocyte competence, as determined by the ability to undergo fertilization or parthenogenic activation and to reach specific cleavage stages at appropriate time intervals, was evaluated. Intracytoplasmic sperm injection resulted in a 59% fertilization rate and a 91% cleavage rate. Parthenogenic activation resulted in a 70% activation rate and an 86% cleavage rate. These data suggest that use of the long-acting form of luprolide acetate in conjunction with controlled ovarian hyperstimulation results in the production of competent, mature oocytes and allows the efficient use of nonhuman primate resources in studies of reproductive function in cynomolgus macaques.

Assisted Reproductive Technologies (ART) With Baboons Generate Live Offspring: A Nonhuman Primate Model for ART and Reproductive Sciences

“…The first two stimulation protocols, used successfully with rhesus macaque females (Davenport et al, 2003; Hewitson et al, 2002; Hewitson et al, 1998; Nusser et al, 2001; Stouffer and Zelinski-Wooten, 2004), altered the inclusion of r-LH and/or GnRH agonist (Table 1). Both Protocol I and II gave equally high total oocyte yields at collection (29-33 total oocytes; Table 1, column k), but provided significantly lower yields of fully mature oocytes for fertilization compared to other stimulation protocols (average: 6-9 usable oocytes; 20-27% of the total oocytes collected; Table 1, column l; p= 0.05).…”

Overriding follicle selection in controlled ovarian stimulation protocols: Quality vs quantity

“…Over the past 15 years, the remarkable increase in use of COS-ART protocols in clinical practice to treat infertile couples [60] has been paralleled by applications of this technology to numerous NHP species, from great apes [61] to baboons [62,63], and various Old World monkeys [19,22,64-66] to New World monkeys [67]. Reports from zoological settings [61,65] as well as many NHP research centers (see also following chapters) illustrate the potential value of this approach to preserve and foster reproduction of endangered primate species or primates of a known genetic character that are valuable for applied research of direct relevance to human health.…”

“…However, a standard or optimal protocol of human gonadotropins has not emerged from clinical protocols in women, or from COS procedures in any NHP species. In macaque species, for example, investigators have employed gonadotropin regimens of hFSH alone [20-22], a combined treatment of hFSH plus hLH [23], and a sequential protocol of hFSH alone followed by an interval of hFSH plus hLH [24-26]. Despite the issues described in subsequent sections, these protocols can successfully generate multiple large antral follicles with fertilizable oocytes both in adult primates and, more recently, in prepubertal monkeys [6,27].…”

“…However, this requires labor-intensive efforts to regularly perform transabdominal ultrasonography and rapid estradiol assays, usually daily from day 7 of treatment. Also, based on their effectiveness and reversibility in macaques, a GnRH agonist [22,23] or antagonist [32,39] can be administered concomitantly throughout or during the last part of the gonadotropin stimulation protocol to assure prevention of an endogenous LH surge (see later section).…”

“…In addition, ART patients are often treated with these drugs prior to starting gonadotropin treatment to permit arbitrary initiation of protocols independent of the menstrual cycle, thereby projecting follicle aspiration for a convenient time during the work week. With the development of second- and third-generation GnRH analogs, these drugs have been administered to macaques prior to [22], throughout [23,32] or in the latter part (unpublished) of the gonadotropin treatment regimen for these purposes. However, effective methods are needed to identify potential nonresponders prior to initiating follicular stimulation protocols.…”