Available online at Theriogenology 76 (2011) Advances in Bovine Reproduction and Embryo Technology

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1 Available online at Theriogenology 76 (2011) Advances in Bovine Reproduction and Embryo Technology Improving post-transfer of bovine embryos produced in vitro: Actions of insulin-like growth factor-1, colony stimulating factor-2 and hyaluronan J. Block a,b, *, P.J. Hansen a, B. Loureiro a, L. Bonilla a a Department of Animal Sciences, University of Florida, Gainesville, Florida, USA b OvaTech LLC, Gainesville, Florida, USA Received 23 March 2011; received in revised form 15 July 2011; accepted 17 July Abstract Technologies for in vitro embryo production have the potential to enhance the efficiency of cattle production systems. However, utilization of in vitro-produced embryos for transfer remains limited throughout much of the world. Despite improvements over the past two decades, problems associated with the production of bovine embryos in vitro still exist which limit the widespread commercial application of this technology. In particular, bovine embryos produced in vitro have a reduced capacity to establish and maintain pregnancy as compared with their in vivo-derived counterparts. Embryo competence for following transfer is improved by in vivo culture in the sheep oviduct, thus indicating that standard embryo culture conditions are sub-optimal. Therefore, one strategy to improve post-transfer is to modify embryo culture media to more closely mimic the in vivo microenvironment. The maternal environment in which the bovine embryo develops in vivo contains various growth factors, cytokines, hormones, and other regulatory molecules. In addition to affecting bovine embryo development in vitro, recent research indicates that embryo competence for following transfer can also be improved when such molecules are added to embryo culture medium. Among the specific molecules that can increase post-transfer embryo are insulin-like growth factor-1 (IGF-1), colony stimulating factor-2 (CSF-2) and hyaluronan. This paper will review the effects IGF-1, CSF-2 and hyaluronan on post-culture embryo viability and discuss the potential mechanisms through which each of these molecules improves post-transfer Elsevier Inc. All rights reserved. Keywords: Cattle; Colony stimulating factor-2; Embryo transfer; Insulin-like growth factor-1; Hyaluronan Contents 1. Introduction Importance of the culture environment for post-culture viability Molecules affecting post-transfer embryo Insulin-like growth factor Effect of IGF-1 on post-transfer embryo * Corresponding author. Tel.: ; fax: address: blockj@ufl.edu (J. Block) X/$ see front matter 2011 Elsevier Inc. All rights reserved. doi: /j.theriogenology

2 J. Block et al. / Theriogenology 76 (2011) Potential mechanisms for improved embryo Colony-stimulating factor Effect of CSF-2 on post-transfer embryo Potential mechanisms for improved embryo Hyaluronan Effect of hyaluronan on post-transfer embryo Potential mechanisms for improved embryo Conclusions Acknowledgments References Introduction The use of in vitro embryo production for transfer in both beef and dairy cattle has the potential to maximize genetic improvement, increase fertility and optimize breeding schemes [1,2]. Given this potential, it is not surprising that over the past decade the number of in vitro-produced embryos transferred worldwide each year has increased from approximately 42,000 to almost 300,000 [3]. Interestingly, this dramatic increase in the utilization of in vitro embryo transfer is almost entirely due to the application of in vitro embryo production in South America, especially Brazil [3]. In fact, outside of South America, embryos produced by superovulation still represent the predominant source of embryos for transfer [3]. Thus, despite the potential for in vitro embryo transfer to improve the efficiency of cattle production, much of the world has yet to fully adopt the use of this technology. Although substantial progress has been made over the past two decades, problems associated with the production of bovine embryos in vitro [4 11] still limit the widespread application of this technology. Improvements in the potential of the bovine embryo derived in vitro to establish and maintain pregnancy following transfer and to give rise to a healthy offspring will be necessary for further adoption of in vitro embryo technologies in commercial settings. An inadequate culture environment is at least one reason for alterations in embryonic function associated with embryo production in vitro [6,7,12,13]. Thus, a potential strategy to improve post-transfer is to modify culture media to more closely mimic the microenvironment found in vivo. Several regulatory molecules present in vivo in the female reproductive tract, including hormones, growth factors and cytokines, can improve early bovine embryo development in vitro. Recent evidence now indicates that such molecules can also enhance embryo competence for following transfer. Among the specific molecules that can increase posttransfer embryo are insulin-like growth factor-1 (IGF-1), colony stimulating factor-2 (CSF-2) and hyaluronan. This paper will review the effects IGF-1, CSF-2 and hyaluronan on post-culture embryo viability and discuss potential mechanisms through which each of these molecules improves post-transfer. 2. Importance of the culture environment for post-culture viability Bovine embryos produced in vitro differ from their in vivo-derived counterparts on many levels. In particular, embryos produced in vitro have altered ultrastructural, metabolic, molecular and physiological features [13 16]. Consequently, post-culture viability can be compromised. Specifically, bovine embryos produced in vitro are more sensitive to cryopreservation [4 7], have reduced embryo and fetal following transfer [8,9], and result in an increased number of fetuses and calves with abnormalities [9 11]. Alterations in post-culture viability of bovine embryos produced in vitro are due, at least in part, to a sub-optimal culture environment. Studies using the sheep oviduct as a model have highlighted this problem, as well as, its consequences for post-culture viability [17]. Embryos produced in vitro have an altered pattern of gene expression [7,12], reduced cryotolerance [6,7], and result in lower pregnancy per embryo transfer and increased calf birth weights following transfer compared with embryos derived in vivo [12].In contrast, in vitro-produced embryos that are cultured in the sheep oviduct have a similar pattern of gene expression [7,12], and a similar capacity to survive cryopreservation [12], establish pregnancies, and give rise to normal calves [12]. These results suggest that specific molecules produced by the reproductive tract are needed for optimal post-culture viability.

3 1604 J. Block et al. / Theriogenology 76 (2011) Molecules affecting post-transfer embryo Embryo development in vivo is regulated in part by oviductal and uterine histotroph, a complex mixture of molecules which includes growth factors, cytokines, hormones, and other regulatory molecules [18]. In vitro, a number of these types of molecules can affect embryo development (See [19,20] for a review on growth factors and cytokines) and in some cases postculture viability. Specific molecules that have been shown to improve embryo competence for post-transfer in cattle are detailed below Insulin-like growth factor-1 The bovine preimplantation embryo expresses the receptor for IGF-1 throughout early development [21] and, in addition to IGF-1 secreted by the liver, IGF-1 is also produced locally by the bovine oviduct [22] and endometrium [23]. The bovine embryo can respond to IGF-1 treatment in vitro and such effects have been well-studied. In particular, numerous studies have reported a positive effect of IGF-1 on development to the blastocyst stage [24 30]. Furthermore, treatment of bovine embryos with IGF-1 can increase blastocyst cell number [28,30] and reduce apoptosis [28,30]. Fig. 1. Treatment of embryos with insulin-like growth factor-1 (IGF-1) improves post-transfer during the hot season, but not the cool season. Each experiment was conducted in Florida using lactating dairy cows. Experiment 1 included 210 cows, Experiment 2 included 308 cows, and Experiment 3 included 225 cows. Data are calving per embryo transfer (Experiments 1 and 3) and pregnancy per embryo transfer at Day 45 of gestation (Experiment 2). Figure is taken from Hansen et al. [57] Effect of IGF-1 on post-transfer embryo Results from three embryo transfer experiments [27,31,32] conducted using lactating dairy cows as recipients indicate that IGF-1 can enhance embryo competence for following transfer. Interestingly, however, the beneficial effect of IGF-1 on post-transfer embryo was only observed when recipients were exposed to heat stress (Fig. 1). Increased rates of pregnancy and calving per embryo transfer obtained in heat-stressed recipients following the transfer of embryos cultured in the presence of IGF-1 are the result of both an increase in the number of embryos that initially establish pregnancy as well as an enhanced capacity of embryos to survive after pregnancy establishment. In the study of Block and colleagues [31], an increase in pregnancy per embryo transfer among heat-stressed recipients that received embryos treated with IGF-1 was detected as early as Day 21 (based on plasma progesterone). Furthermore, recipients that received IGF-1 treated embryos in the summer had less pregnancy loss between Days 21 and 30 than recipients that received control embryos. Similar findings were also reported by Loureiro and others [32] in which heat-stressed recipients that received embryos cultured with IGF-1 had greater pregnancy per embryo transfer at Days and less pregnancy loss between Days and term than recipients that received control embryos Potential mechanisms for improved embryo The basis for improved of IGF-1 treated embryos following transfer to heat-stressed recipients is not clear. Insulin-like growth factor-1 is a factor that can help protect embryos from several stresses, including heat shock [33 35]. Thus, it is likely that IGF-1 treatment results in blastocysts with an increased resistance to maternal hyperthermia. It is also possible that IGF-1 helps to overcome alterations in reproductive function caused by heat stress. For instance, exposure to heat shock increases secretion of prostaglandin F 2 from the endometrium of pregnant cows [36] and decreases secretion of interferon- (IFN- ) from Day-17 bovine conceptuses [37]. Although IGF-1 did not affect the secretion of IFN- from Day-14 conceptuses [38] recovered from non-lactating cows during the cool season, it cannot be ruled out that IGF-1 helps prevent a reduction in IFN- secretion induced by hyperthermia. At the cellular level, addition of IGF-1 to bovine embryo culture can increase blastocyst cell number [28,30], alter cell allocation to the inner cell mass (ICM) [28] or trophectoderm [26,39], and reduce apoptosis in blastocysts [28,30]. However, in our laboratory,

4 J. Block et al. / Theriogenology 76 (2011) there was no effect of IGF-1 on these parameters [40], suggesting that such variables are likely not important for the enhanced of IGF-1 treated bovine embryos during the summer. In contrast, the culture of embryos in the presence of IGF-1 has been reported to alter gene expression in bovine blastocyst-stage embryos [40]. Whether or not these changes induced by IGF-1 at the molecular level are important for enhanced embryo during heat stress is not known Colony-stimulating factor-2 Also known as granulocyte-macrophage colonystimulating factor, CSF -2 is present in both the oviduct and endometrium of the cow throughout the estrous cycle, with the greatest expression in epithelial cells [41,42]. Addition of CSF-2 to bovine embryo culture medium has been reported to increase the proportion of embryos that develop to the blastocyst stage in culture [32,43]. Moreover, blastocysts that develop following CSF-2 treatment had a tendency for more cells in the ICM and a greater ratio of ICM to trophectoderm cells [32] Effect of CSF-2 on post-transfer embryo Addition of CSF-2 to embryo culture medium can increase embryo following transfer in mice [44]. In two recent experiments, Loureiro and others [32] tested whether the of bovine embryos following transfer could be improved by CSF-2 treatment. In the first experiment, embryos were cultured in the presence of CSF-2 from Days 1 to 7 and then transferred into lactating dairy cows during the summer. Culture of embryos with CSF-2 did not affect pregnancy per embryo transfer at Days of gestation or the proportion of cows calving (Table 1). However, recipients that received embryos cultured in the presence of CSF-2 had less pregnancy loss between Days of gestation and term (Table 1). In the second experiment, embryos were cultured in the presence of CSF-2 from Days 5 to 7, and then transferred to lactating dairy cows primarily during the cool season. Pregnancy per embryo transfer at Days and the proportion of cows calving were greater for recipients that received embryos treated with CSF-2 (Table 2). Although not significant, pregnancy loss from Days to term was numerically lower for cows that received CSF-2 treated embryos (Table 2). When data from both experiments were combined, pregnancy loss between Day and term was significantly less for embryos cultured in the presence of CSF-2. It is not clear why treatment of embryos with CSF-2 starting at Day 1 did not affect pregnancy per embryo Table 1 Effects of colony-stimulating factor-2 (CSF2) added at Day 1 after insemination on pregnancy per embryo transfer at Day 30 35, calving rate and pregnancy loss after initial pregnancy diagnosis.*,, Treatment Pregnancy per embryo transfer Calving rate Pregnancy loss Control 35% (18/52) 27% (14/52) 22% (4/18) CSF2 35% (18/51) 35% (18/51) 0% (0/18) * Table is adapted from Loureiro et al [32]. Data represent the proportion of recipients diagnosed as pregnant at Days (number of pregnant recipients/total recipients). Data represent the proportion of recipients that calved (number of recipients calving/total recipients). Data represent the proportion of recipients pregnant at Days that lost their pregnancy before term (number lost pregnancy/number pregnant on Days 30 35)., Within a column, means without a common superscript differ (P 0.05). transfer, whereas treatment with CSF-2 starting at Day 5 did. Blastocyst development was increased by CSF-2, regardless of whether it was added on Day 1 or Day 5 after fertilization [32]. The first experiment, in which CSF-2 was added beginning at Day 1, was conducted during the summer using heat-stressed cows. It is well known that heat stress can compromise embryonic [45]; therefore, it may have negated any beneficial effect of CSF-2 treatment in that experiment. Additional research is necessary to confirm whether CSF-2 treatment can improve pregnancy per embryo transfer during heat stress. Nonetheless, the results of the two Table 2 Effects of colony-stimulating factor-2 (CSF2) added at Day 5 after insemination on pregnancy per embryo transfer at Days 30-35, calving rate, and pregnancy loss after initial pregnancy diagnosis*,, Treatment Pregnancy per embryo transfer Calving rate Pregnancy loss Control 34% (27/79) 23% (17/74) 22% (5/22) CSF2 43% (47/107) 37% (39/104) 11% (5/44) * Table is adapted from Loureiro et al [32]. Data represent the proportion of recipients diagnosed as pregnant at Days (number of pregnant recipients/total recipients). Data represent the proportion of recipients that calved (number of recipients calving/total recipients). Data represent the proportion of recipients pregnant at Days that lost their pregnancy before term (number lost pregnancy/number pregnant on Days 30 35)., Within a column, means without a common superscript differ (P 0.05).

5 1606 J. Block et al. / Theriogenology 76 (2011) studies clearly indicate that embryos cultured in the presence of CSF-2 have an enhanced capability to survive to term following establishment of pregnancy Potential mechanisms for improved embryo The ability of CSF-2 treatment to increase pregnancy per embryo transfer at Days of gestation is caused, at least in part, by actions of CSF-2 that promote embryo in the first week following transfer. In a recent experiment [46] in which embryos were treated with CSF-2, transferred at Day 7 after fertilization and then recovered non-surgically at Day 15, the proportion of recipients from which an embryo was recovered increased in cows that received CSF-2 treated embryos. Moreover, of the embryos recovered at Day 15, CSF-2 increased embryo size and IFN- secretory activity [46]. Therefore, it can be postulated that CSF-2 treatment improves pregnancy per embryo transfer by enhancing the capacity of embryos to prevent luteolysis during the critical period of maternal recognition of pregnancy. Interestingly, CSF-2 treatment had no effect on the expression of genes (as analyzed by microarray) in filamentous embryos recovered at Day 15 [46]. Thus, the effect of CSF-2 to reduce pregnancy loss after Days is not likely the result of CSF-2 induced changes in global transcription at Day 15. Actions of CSF-2 to regulate embryo development before embryo transfer are also likely important for improving post-transfer embryo. Embryos cultured with CSF-2 have increased numbers of ICM cells and also a greater ratio of ICM to trophectoderm cells [32]. Moreover, results from a microarray analysis of Day-6 embryos treated with CSF-2 starting on Day 5 indicate that CSF-2 treatment alters the expression of genes controlling developmental processes and apoptosis [47]. In particular, CSF-2 acts to increase the expression of genes regulating mesoderm formation and epithelial to mesenchymal transition and decrease the expression of genes regulating neural cell differentiation [47]. An additional effect of CSF-2 was to decrease genes involved in apoptosis and increase genes that regulate cell [47]. Perhaps, CSF-2 induced changes in cell fate and result in an embryo with enhanced competence for during the embryonic and fetal periods Hyaluronan Hyaluronan is a glycosaminoglycan that is a component of oviductal and uterine fluids in the cow [48]. The receptor for hyaluronan, CD44, is expressed by pre-implantation bovine embryos [49]. Effects of hyaluronan on bovine embryo development in vitro are Table 3 Effects of hyaluronan and embryo stage on pregnancy rates following transfer to lactating recipients.* Treatment Embryo stage Pregnancy rate d Control morula blastocysts 18.5% (15/81) Hyaluronan morula blastocysts 28.6% (20/70) Control expanded blastocysts 38.3% (31/81) Hyaluronan expanded blastocysts 29.5% (23/78) * Table was adapted from Block et al [52]. Effects of treatment (P 0.10), stage of development (P 0.05), and treatment x stage of development (P 0.05). variable. In some cases, addition of hyaluronan to bovine embryo culture medium has increased development to the blastocyst stage [50 52], whereas in other cases there was no effect [53,54]. Results of a study by Palasz and colleagues [55] indicate that the effect hyaluronan on bovine embryo development in vitro depends upon the medium used for embryo culture. Although actions of hyaluronan to promote development to the blastocyst stage in vitro are inconsistent, treatment of bovine embryos with hyaluronan during culture results in blastocysts with enhanced capacity to survive cryopreservation [52 54] Effect of hyaluronan on post-transfer embryo As with CSF-2, effects of hyaluronan on embryo following transfer were first studied using mice [56]. In this study, hyaluronan increased pregnancy rates following transfer when it was added to both the culture medium and embryo transfer medium, or only to the embryo transfer medium. In cattle, only one study has evaluated the effect of addition of hyaluronan to embryo culture on subsequent pregnancy establishment following embryo transfer [52]. The results of this study suggest that hyaluronan can improve the posttransfer of less-advanced bovine embryos. In particular, hyaluronan increased pregnancy per embryo transfer in recipients that received embryos at the morula and blastocyst stages, but there was no effect of hyaluronan treatment for recipients that received expanded blastocyst-stage embryos (Table 3) Potential mechanisms for improved embryo The limited amount of research regarding the effect of hyaluronan treatment during culture on embryo following transfer makes it difficult to formulate inferences regarding the potential mechanism by which hyaluronan can improve the competence of less-developed embryos. Addition of hyaluronan to bovine embryo

6 J. Block et al. / Theriogenology 76 (2011) culture improves the capacity of embryos to survive following cryopreservation [52 54]. In addition, hyaluronan can alter the expression of certain developmentally important genes [54,55]. Perhaps, alterations in early embryo development caused by hyaluronan are more important for the competence of morula and blastocyst stage embryos because such embryos are slowerdeveloping when compared with expanded blastocysts. Further research is needed to better understand how hyaluronan can improve post-transfer. 4. Conclusions The capacity of the bovine embryo derived in vitro to establish and maintain pregnancy and result in a live calf following transfer is compromised by a sub-optimal culture environment. It is possible to overcome the suboptimal culture environment and enhance embryo competence for following transfer by modifying embryo culture medium with specific regulatory molecules produced by the reproductive tract. Among the specific regulatory molecules that can improve post-transfer are IGF-1, CSF-2, and hyaluronan. Each of these three molecules appears to have somewhat distinct effects on embryo post-transfer. For instance, IGF-1 improves pregnancy and calving per embryo transfer only when recipients are exposed to heat stress. Hyaluronan treatment enhances pregnancy following transfer of less-developed embryos (morula and blastocysts), but not when more advanced embryos (expanded blastocysts) are transferred. Therefore, it may be possible to further enhance post-transfer by using these molecules, either alone or in combination, if their mechanisms of action result in complementary effects on embryo. Incorporation of these molecules for in vitro embryo culture has the potential to increase the efficiency of embryo transfer under commercial settings. Acknowledgments Original research from the laboratory of P.J. Hansen was supported by National Research Initiative Competitive grants no and from the USDA Cooperative State Research, Education, and Extension Service, grant no. US from the Binational Agricultural Research and Development Fund and grants from the Southeastern Milk Inc. Dairy Checkoff Fund. References [1] Hansen PJ, Block J. Towards an embryocentric world: the current and potential uses of embryo technologies in dairy production. Reprod Fertil Dev 2004;16:1 14. [2] Hansen PJ. Realizing the promise of IVF in cattle - an overview. Theriogenology 2006;65: [3] Stroud B. Statistics and Data Retrieval Committee Report: The year 2009 worldwide statistics of embryo transfer in domestic farm animals. International Embryo Transfer Newsletter. 2010; 28: [4] Pollard JW, Leibo SP. Comparative cryobiology of in vitro and in vivo derived bovine embryos. Theriogenology 1993;39:287 [abstract]. [5] Rizos D, Ward F, Duffy P, Boland MP, Lonergan P. Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: implications for blastocyst yield and blastocyst quality. Mol Reprod Dev, 2002;61: [6] Enright BP, Lonergan P, Dinnyes A, Fair T, Ward FA, Yang X, Boland MP. Culture of in vitro produced bovine zygotes in vitro vs in vivo: implications for early embryo development and quality. Theriogenology 2000;54: [7] Rizos D, Gutierrez-Adan A, Perez-Garnelo S, De La Fuente J, Boland MP, Lonergan P. Bovine embryo culture in the presence or absence of serum: implications for blastocyst development, cryotolerance, and messenger RNA expression. Biol Reprod 2003;68: [8] Hasler JF, Henderson WB, Hurtgen PJ, Jin ZQ, McCauley AD, Mower SA, Neely B, Shuey LS, Stokes JE, Trimme SA. Production, freezing and transfer of bovine IVF embryos and subsequent calving results. Theriogenology 1995;43: [9] Farin PW, Piedrahita JA, Farin CE. Errors in development of fetuses and placentas from in vitro-produced bovine embryos. Theriogenology 2006;65: [10] van Wagtendonk-de Leeuw AM, Aerts BJ, den Daas JH. Abnormal offspring following in vitro production of bovine preimplantation embryos: a field study. Theriogenology 1998;49: [11] van Wagtendonk-de Leeuw AM, Mullaart E, de Roos AP, Merton JS, den Daas JH, Kemp B, de Ruigh L. Effects of different reproduction techniques: AI MOET or IVP, on health and welfare of bovine offspring. Theriogenology 2000;53: [12] Lazzari G, Wrenzycki C, Herrmann D, Duchi R, Kruip T, Niemann H, Galli C. Cellular and molecular deviations in bovine in vitro-produced embryos are related to the large offspring syndrome. Biol Reprod 2002;67: [13] Lonergan P, Fair T, Corcoran D, Evans AC. Effect of culture environment on gene expression and developmental characteristics in IVF-derived embryos. Theriogenology 2006;65: [14] Crosier AE, Farin PW, Dykstra MJ, Alexander JE, Farin CE. Ultrastructural morphometry of bovine blastocysts produced in vivo or in vitro. Biol Reprod 2001;64: [15] Khurana NK, Niemann H. Energy metabolism in preimplantation bovine embryos derived in vitro or in vivo. Biol Reprod 2000;62: [16] Farin CE, Farin PW, Piedrahita JA. Development of fetuses from in vitro-produced and cloned bovine embryos. J Anim Sci 2004;82(Suppl.1):E53 E62.

7 1608 J. Block et al. / Theriogenology 76 (2011) [17] Lonergan P, Fair T, Corcoran D, Evans AC. Effect of culture environment on gene expression and developmental characteristics in IVF-derived embryos. Theriogenology 2006;65: [18] Spencer TE, Bazer FW. Uterine and placental factors regulating conceptus growth in domestic animals. J Anim Sci 2004;84:E4 E13. [19] Hardy K, Spanos S. Growth factor expression and function in the human and mouse embryo. J Endocrinol 2002;172: [20] Diaz-Cueto L, Gerton GL. The influence of growth factors on the development of preimplantation mammalian embryos. Arch Med Res 2001;32: [21] Wang LM, Feng HL, Ma YZh, Cang M, Li HJ, Yan Zh, Zhou P, Wen, JX, Bou S, Liu DJ. Expression of IGF receptors and its ligands in bovine oocytes and preimplantation embryos. Anim Reprod Sci 2009;114: [22] Pushpakumara PG, Robinson RS, Demmers KJ, Mann GE, Sinclair KD, Webb R, Wathes DC. Expression of the insulinlike growth factor (IGF) system in the bovine oviduct at oestrus and during early pregnancy. Reproduction 2002;123: [23] Robinson RS, Mann GE, Gadd TS, Lamming GE, Wathes DC. The expression of the IGF system in the bovine uterus throughout the oestrous cycle and early pregnancy. J Endocrinol 2000; 165: [24] Palma GA, Muller M, Brem G. Effect of insulin-like growth factor I (IGF-I) at high concentrations on blastocyst development of bovine embryos produced in vitro. J Reprod Fertil 1997;110: [25] Prelle K, Stojkovic M, Boxhammer K, Motlik J, Ewald D, Arnold GJ, Wolf E. Insulin-like growth factor I (IGF-I) and long R(3)IGF-I differently affect development and messenger ribonucleic acid abundance for IGF-binding proteins and type I IGF receptors in in vitro produced bovine embryos. Endocrinology 2001;142: [26] Moreira F, Paula-Lopes FF, Hansen PJ, Badinga L, Thatcher WW. Effects of growth hormone and insulin-like growth factor-i on development of in vitro derived bovine embryos. Theriogenology 2002;57: [27] Block J, Drost M, Monson RL, Rutledge JJ, Rivera RM, Paula- Lopes FF, Ocon OM, Krininger CE 3rd, Liu J, Hansen PJ. Use of insulin-like growth factor-i during embryo culture and treatment of recipients with gonadotropin-releasing hormone to increase pregnancy rates following the transfer of in vitro-produced embryos to heat-stressed, lactating cows. J Anim Sci 2003;81: [28] Byrne AT, Southgate J, Brison DR, Leese HJ. Regulation of apoptosis in the bovine blastocyst by insulin and the insulin-like growth factor (IGF) superfamily. Mol Reprod Dev 2002;62: [29] Sirisathien S, Hernandez-Fonseca HJ, Brackett BG. Influences of epidermal growth factor and insulin-like growth factor-i on bovine blastocyst development in vitro. Anim Reprod Sci 2003;77: [30] Sirisathien S, Brackett BG. TUNEL analyses of bovine blastocysts after culture with EGF and IGF-I. Mol Reprod Dev 2003; 65:51 6. [31] Block J, Hansen PJ. Interaction between season and culture with insulin-like growth factor-1 on of in vitro produced embryos following transfer to lactating dairy cows. Theriogenology 2007;67: [32] Loureiro B, Bonilla L, Block J, Fear JM, Bonilla AQ, Hansen PJ. Colony-stimulating factor (CSF-2) improves development and posttransfer of bovine embryos produced in vitro. Endocrinology 2009;150: [33] Jousan FD, Hansen PJ. Insulin-like growth factor-i as a factor for the bovine preimplantation embryo exposed to heat shock. Biol Reprod 2004;71: [34] Jousan FD, Hansen PJ. Insulin-like growth factor-i promotes resistance of bovine preimplantation embryos to heat shock through actions independent of its anti-apoptotic actions requiring PI3K signaling. Mol Reprod Dev 2007;74: [35] Bonilla AQ, Oliveira LJ, Ozawa M, Newsom EM, Lucy MC, Hansen PJ. Developmental changes in thermoprotective actions of insulin-like growth factor-1 on the preimplantation bovine embryo. 2011;332: [36] Putney DJ, Gross TS, Thatcher WW. Prostaglandin secretion by endometrium of pregnant and cyclic cattle at day 17 after oestrus in response to in-vitro heat stress. J Reprod Fertil 1988;84: [37] Putney DJ, Malayer JR, Gross TS, Thatcher WW, Hansen PJ, Drost M. Heat stress-induced alterations in the synthesis and secretion of proteins and prostaglandins by cultured bovine conceptuses and uterine endometrium. Biol Reprod 1988;39: [38] Block J, Fischer-Brown A, Rodina TR, Ealy AD, Hansen PJ. Development of in vitro-produced embryos at day 14 of gestation as modified by addition of insulin-like growth factor-1 to culture medium. Theriogenology 2007;68: [39] Makarevich AV, Markkula M. Apoptosis and cell proliferation potential of bovine embryos stimulated with insulin-like growth factor I during in vitro maturation and culture. Biol Reprod 2002;66: [40] Block J, Wrenzycki C, Niemann H, Herrmann D, Hansen PJ. Effects of insulin-like growth factor-1 on cellular and molecular characteristics of bovine blastocysts produced in vitro. Mol Reprod Dev 2008;75: [41] de Moraes AA, Paula-Lopes FF, Chegini N, Hansen PJ. Localization of granulocyte macrophage colony-stimulating factor in the bovine reproductive tract. J Reprod Immunol 1999;42: [42] Emond V, MacLaren LA, Kimmins S, Arosh JA, Fortier MA, Lambert RD. Expression of cyclooxygenase-2 and granulocyte macrophage colony-stimulating factor in the endometrial epithelium of the cow is up-regulated during early pregnancy and in response to intrauterine infusions of interferon-tau. Biol Reprod 2004;70: [43] de Moraes AAS, Hansen, PJ. Granulocyte macrophage colonystimulating factor promotes development of in vitro produced bovine embryos. Biol Reprod 1997;57: [44] Sjöblom C, Roberts CT, Wikland M, Robertson SA. Granulocyte-macrophage colony-stimulating factor alleviates adverse consequences of embryo culture on fetal growth trajectory and placental morphogenesis. Endocrinology 2005;146: [45] Hansen PJ. To be or not to be determinants of embryonic following heat shock. J Anim Sci 2007;68(Suppl 1): S40 S48. [46] Loureiro B, Block J, Favoreto MG, Carambula S, Penningtion KA, Ealy AD, Hansen PJ. Consequences of conceptus exposure to colony stimulating factor 2 on, elongation, interferon-tau secretion and gene expression. Reproduction 2011;141: [47] Loureiro B, Oliveira LJ, Favoreto MG, Hansen PJ. Changes in the transcriptome of the bovine preimplantation embryo caused by colony stimulating factor 2. PLoS One 2011; submitted. [48] Lee CN, Ax RL. Concentration and composition of glycoaminoglycans in the female bovine reproductive tract. J Dairy Sci 1984;67:

8 J. Block et al. / Theriogenology 76 (2011) [49] Furnus CC, Valcarcel A, Dulout FN, Errecalde A. The hyaluronic acid receptor (CD44) is expressed in bovine oocytes and early stage embryos. Theriogenology 2003;60: [50] Furnus, CC, de Mantos, DG, Martinez AG. Effect of hyaluronic acid on development of in vitro produced bovine embryos. Theriogenology 1998;49: [51] Jang G, Lee BC, Kang KC, Hwang WS. Effect of glycosaminoglycans on the preimplantation development of embryos derived from in vitro fertilization and somatic cell nuclear transfer. Reprod Fertil Dev 2003;15: [52] Block J, Bonilla L, Hansen PJ. Effect of addition of hyaluronan to embryo culture medium on of bovine embryos in vitro following vitrification and establishment of pregnancy after transfer to recipients. Theriogenology 2009;71: [53] Lane M, Maybach JM, Hooper K, Hasler JF, Gardner DK. Cryo- and development of bovine blastocysts are enhanced by culture with recombinant albumin and hyaluronan. Mol Reprod Dev 2003;64: [54] Palasz AT, Breña PB, Martinez MF, Perez-Garnelo SS, Ramirez MA, Gutíerrez-Adán A, De la Fuente J. Development, molecular composition and freeze tolerance of bovine embryo cultured in TCM-199 supplemented with hyaluronan. Zygote 2008; 16: [55] Palasz, AT, Rodriquez-Martinez H, Beltran-Breña P, Perez- Garnelo S, Martinez MF, Gutierrez-Adan A, de la Fuente J. Effects of hyaluronan, BSA, and serum on bovine embryo in vitro development, ultrastructure, and gene expression patterns. Mol Reprod Develop 2006;73: [56] Gardner DK, Rodriegez-Martinez H, Lane M. Fetal development after transfer is increased by replacing protein with the glycosaminoglycan hyaluronan for mouse embryo transfer and culture. Hum Reprod 1999;14: [57] Hansen PJ, Block J, Louriero B, Bonilla L, Hendricks KEM. Effects of gamete source and culture conditions on the competence of in-vitro produced embryos for post-transfer in cattle. Reprod Fertil Dev 2010;22:59 66.