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Dieter Schams - One of the best experts on this subject based on the ideXlab platform.
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expression pattern of hif1alpha and vasohibins during follicle maturation and Corpus Luteum Function in the bovine ovary
Reproduction in Domestic Animals, 2017Co-Authors: Bajram Berisha, Dieter Schams, Daniela Rodler, Fred Sinowatz, Michael W PfafflAbstract:Contents The aim of this study was to characterize expression patterns of hypoxia-inducible factor-1alpha (HIF1A) and vasohibin family members (VASH1 and VASH2) during different stages of ovarian Function in cow. Experiment 1: Antral follicle classification occurred by follicle size and estradiol-17beta (E2) concentration in the follicular fluid into 5 groups ( 180 E2 ng/ml). Experiment 2: Corpora lutea (CL) were assigned to the following stages: days 1–2, 3–4, 5–7, 8–12, 13–16 and >18 (after regression) of oestrous cycle and of pregnancy (months 1–2, 3–4, 6–7, >8). Experiment 3: Cows on days 8–12 were injected with a prostaglandin F2alpha (PGF) analogue and CL were collected before and 0.5, 2, 4, 12, 24, 48 and 64 hr after PGF injection. Expression of mRNA was measured by qPCR, steroid hormone concentration by EIA and localization by immunohistochemistry. HIF1A mRNA expression in our study increases significantly in follicles during final maturation. The highest HIF1A mRNA expression was detected during the early luteal phase, followed by a significant decrease afterwards. In contrast, the mRNA of vasohibins in small follicle was high, followed by a continuous and significant downregulation in preovulatory follicles. The obtained results show a remarkable inverse expression and localization pattern of HIF1A and vasohibins during different stages of ovarian Function in cow. These results lead to the assumption that the examined factors are involved in the local mechanisms regulating angiogenesis and that the interactions between proangiogenic (HIF1A) and antiangiogenic (vasohibins) factors impact all stages of bovine ovary Function.
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effect of prostaglandin f2 alpha on local luteotropic and angiogenic factors during induced Functional luteolysis in the bovine Corpus Luteum
Biology of Reproduction, 2010Co-Authors: Bajram Berisha, H H D Meyer, Dieter SchamsAbstract:The essential role of endometrial prostaglandin F2 alpha (PTGF) for induction of the Corpus Luteum (CL) regression is well documented in the cow. However, the acute effects of PTGF on known local luteotropic factors (oxytocin [OXT] and its receptor, insulin-like growth factor [IGF] 1, and progesterone and its receptor), the principal angiogenic factor vascular endothelial growth factor (VEGF) A and the capillary destabilization factor angiopoietin (ANGPT) 2 were not thoroughly studied in detail. The aim of this study was therefore to evaluate the tissue concentration of these factors during PTGF induced luteolysis. In addition the mRNA expression of progesterone receptor (PGR), OXT receptor (OXTR), IGF1, IGFBP1, ANGPT1, and ANGPT2 was determined at different times after PTGF treatment. Cows (n ¼ 5 per group) in the mid-luteal phase (Days 8–12, control group) were injected with the PTGF analog (cloprostenol), and CL were collected by transvaginal ovariectomy at 0.5, 2, 4, 12, 24, 48, and 64 h after injection. The mRNA expression was analyzed by quantitative real-time PCR, and the protein concentration was evaluated by enzyme immunoassay or radioimmunoassay. Progesterone concentrations, as well as mRNA expression of PGR, in CL tissue were significantly downregulated by 12 h after PTGF. Tissue OXT peptide and OXTR mRNA decreased significantly after 2 h, followed by a continuous decrease of OXT mRNA. IGF1 and VEGFA protein already decreased after 0.5 h. By contrast, the IGFBP1 mRNA was up-regulated significantly after 2 h to a high plateau. ANGPT2 protein and mRNA significantly increased during the first 2 h, followed by a steep decrease after 4 h. The acute decrease of local luteotropic activity and acute changes of ANGPT2 and VEGFA suggest that modulation of vascular stability may be a key component in the cascade of events leading to Functional luteolysis. angiogenic factors, Corpus Luteum Function, gene regulation, luteolysis, luteotropic factors
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effect of prostaglandin f2 alpha on local luteotropic and angiogenic factors during induced Functional luteolysis in the bovine Corpus Luteum
Biology of Reproduction, 2010Co-Authors: Bajram Berisha, H H D Meyer, Dieter SchamsAbstract:The essential role of endometrial prostaglandin F2 alpha (PTGF) for induction of the Corpus Luteum (CL) regression is well documented in the cow. However, the acute effects of PTGF on known local luteotropic factors (oxytocin [OXT] and its receptor, insulin-like growth factor [IGF] 1, and progesterone and its receptor), the principal angiogenic factor vascular endothelial growth factor (VEGF) A and the capillary destabilization factor angiopoietin (ANGPT) 2 were not thoroughly studied in detail. The aim of this study was therefore to evaluate the tissue concentration of these factors during PTGF induced luteolysis. In addition the mRNA expression of progesterone receptor (PGR), OXT receptor (OXTR), IGF1, IGFBP1, ANGPT1, and ANGPT2 was determined at different times after PTGF treatment. Cows (n ¼ 5 per group) in the mid-luteal phase (Days 8–12, control group) were injected with the PTGF analog (cloprostenol), and CL were collected by transvaginal ovariectomy at 0.5, 2, 4, 12, 24, 48, and 64 h after injection. The mRNA expression was analyzed by quantitative real-time PCR, and the protein concentration was evaluated by enzyme immunoassay or radioimmunoassay. Progesterone concentrations, as well as mRNA expression of PGR, in CL tissue were significantly downregulated by 12 h after PTGF. Tissue OXT peptide and OXTR mRNA decreased significantly after 2 h, followed by a continuous decrease of OXT mRNA. IGF1 and VEGFA protein already decreased after 0.5 h. By contrast, the IGFBP1 mRNA was up-regulated significantly after 2 h to a high plateau. ANGPT2 protein and mRNA significantly increased during the first 2 h, followed by a steep decrease after 4 h. The acute decrease of local luteotropic activity and acute changes of ANGPT2 and VEGFA suggest that modulation of vascular stability may be a key component in the cascade of events leading to Functional luteolysis. angiogenic factors, Corpus Luteum Function, gene regulation, luteolysis, luteotropic factors
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regulation of Corpus Luteum Function in cattle an overview
Reproduction in Domestic Animals, 2004Co-Authors: Dieter Schams, Bajram BerishaAbstract:Contents The Corpus Luteum (CL) is a transient reproductive gland that produces progesterone (P), required for the establishment and maintenance of pregnancy. Although the regulation of bovine luteal Function has been studied for several decades, many of the regulatory mechanisms involved are incompletely understood. We are far from understanding how these complex mechanisms Function in unison. The purpose of this overview is to stress important steps of regulation during the lifetime of CL. In the first part, the importance and regulation of angiogenesis and blood flow during CL formation is described. The results underline the importance of growth factors especially of vascular endothelial growth factor A (VEGF A) and basic fibroblast growth factor (FGF-2) for development and completion of a dense network of capillaries. In the second part, the regulation of Function by endocrine/paracrine- and autocrine-acting regulators is discussed. There is now more evidence that besides the main endocrine hormones LH and GH local regulators as growth factors, peptides, steroids and prostaglandins are important modulators of luteal Function. During early CL development until mid-luteal stage oxytocin, prostaglandins and P itself stimulate luteal cell proliferation and Function supported by the luteotropic action of a number of growth factors. The still high mRNA expression, protein concentration and localization of growth factors [VEGF, FGF-1, FGF-2, insulin-like growth factors (IGFs)] in the cytoplasm of luteal cells during mid-luteal stage suggest maintenance (survival) Functions for growth factors. In the absence of pregnancy regression (luteolysis) of CL occurs. Progesterone itself regulates the length of the oestrous cycle by influencing the timing of the luteolytic signal prostaglandin F2α (PGF2α) from the endometrium. The cascade of mediators afterwards is very complex and still not well-elucidated. Evidence is given for participation of blood flow, inflammatory cytokines, vasoactive peptides (angiotensin II and endothelin-1), reactive oxygen species, angiogenic growth factors (VEGFs, FGFs, IGFs) and decrease of the classical luteotropic components as LH-R, GH-R, P450scc and 3β-HSD. Despite of differences in methodology and interpretations, progress has been made and will continue to be made.
Tomas J Acosta - One of the best experts on this subject based on the ideXlab platform.
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effect of elevated temperatures on bovine Corpus Luteum Function expression of heat shock protein 70 cell viability and production of progesterone and prostaglandins by cultured luteal cells
Animal Production Science, 2014Co-Authors: Makoto Iwazawa, Tomas J AcostaAbstract:Summer heat stress lowers fertility in cattle in hot environments by influencing oocyte quality, follicular activity and progesterone (P4) level in blood plasma. However, the mechanisms by which elevated temperature influences Corpus Luteum Function remain unclear. Elevated temperature has generally been known to upregulate the gene expression of heat-shock protein (HSP) 70 in a variety of cell types. To clarify the direct effects of elevated temperature on bovine Corpus Luteum Function, we examined the expressions of HSP70, cell viability and the production of P4 and prostaglandins (PGs) in luteal cells cultured at 37.5°C (normal temperature in our culture system), 39.0°C (moderately elevated temperature) or 41.0°C (severely elevated temperature) for 12 or 24 h. HSP70 mRNA expression was increased by incubation at 39.0°C for 12 h and at 41.0°C for 12 and 24 h, whereas HSP70 protein expression was not significantly affected. The viability of luteal cells cultured for 24 h, measured by flow cytometry with propidium iodide staining, was not significantly affected by temperature. Interestingly, the production of P4 by cultured luteal cells was higher at 39.0°C than at 37.5°C after 12 and 24 h of incubation. The production of PGF2α was higher at 39.0°C and 41.0°C than at 37.5°C after 12 and 24 h of incubation. The production of PGE2 was higher at 41.0°C than at 37.5°C after 24 h of incubation. The overall results suggested that elevated temperature does not negatively affect luteal Function, and that the low fertility observed during summer is not due to a direct effect of elevated temperature on luteal cells.
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anti apoptotic roles of prostaglandin e2 and f2alpha in bovine luteal steroidogenic cells
Biology of Reproduction, 2008Co-Authors: Anom Bowolaksono, Tomas J Acosta, Ryo Nishimura, Takuo Hojo, Ryosuke Sakumoto, Kiyoshi OkudaAbstract:Production of prostaglandins (PGs) and expression of their receptors have been demonstrated in bovine Corpus Luteum (CL). The aim of the present study was to determine whether PGE2 and PGF2alpha have roles in bovine luteal steroidogenic cell (LSC) apoptosis. Cultured bovine LSCs obtained at the midluteal stage (Days 8–12 of the cycle) were treated for 24 h with PGE2 (0.001–1 lM) and PGF2alpha (0.001–1 lM). Prostaglandin E2 (1 lM) and PGF2alpha (1 lM) significantly stimulated progesterone (P4) production and reduced the levels of cell death in the cells cultured with or without tumor necrosis factor alpha (TNF)/interferon gamma (IFNG), in the presence and absence of FAS ligand (P , 0.05). Furthermore, DNA fragmentation induced by TNF/IFNG was observed to be suppressed by PGE2 and PGF2alpha. Prostaglandin E2 and PGF2alpha also attenuated mRNA expression of caspase 3 and caspase 8, as well as caspase 3 activity (P , 0.05) in TNF/IFNGtreated cells. FAS mRNA and protein expression were decreased only by PGF2alpha (P , 0.05). A specific P4 receptor antagonist (onapristone) attenuated the apoptosis-inhibitory effects of PGE2 and PGF2alpha in the absence of TNF/IFNG (P , 0.05). A PG synthesis inhibitor (indomethacin) reduced cell viability in PGE2- and PGF2alpha-treated cells (P , 0.05). A specific inhibitor of cyclooxygenase (PTGS), PTGS2 (NS-398), also reduced cell viability, whereas an inhibitor of PTGS1 (FR122047) did not affect it. The overall results suggest that PGE2 and PGF2alpha locally play luteoprotective roles in bovine CL by suppressing apoptosis of LSCs. apoptosis, Corpus Luteum, Corpus Luteum Function, progesterone, prostaglandins
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role of intraluteal prostaglandin f2α progesterone and oxytocin in basal and pulsatile progesterone release from developing bovine Corpus Luteum
Prostaglandins & Other Lipid Mediators, 2006Co-Authors: Tomas J Acosta, Wojciech Pilawski, Katarzyna M Deptula, Kiyoshi Okuda, Dariusz J SkarzynskiAbstract:Abstract The present study examined the role of intra-luteal prostaglandin (PG) F 2α , progesterone (P4) and oxytocin (OT) on the Corpus Luteum Function by using specific hormone antagonists. Luteal cells from the developing CL (days 5–7 of the estrous cycle) were exposed to P4 antagonist (onapristone, OP, 10 −4 M), OT antagonist (atosiban, AT; 10 −6 M) or indomethacin (INDO; 10 −4 M), for 12 h and then stimulated with PGF 2α (10 −8 M) for 4 h. Pre-treatment of the cells with OP, AT or INDO resulted in an increase in P4 secretion in response to PGF 2α . To examine the temporal effects of P4, OT and PGs on P4 secretion, dispersed luteal cells were pre-exposed to OP, AT or INDO for 1, 2, 4, 6 or 12 h. Prostaglandin F 2α stimulated P4 secretion ( P P P 2α , OT, and P4 are components of an autocrine/paracrine intra-ovarian regulatory system responsible for the episodic (pulsatile) release of P4 from the bovine CL during the early luteal phase.
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blood flow a key regulatory component of Corpus Luteum Function in the cow
Domestic Animal Endocrinology, 2005Co-Authors: Akio Miyamoto, Koumei Shirasuna, Missaka P B Wijayagunawardane, Sho Watanabe, M Hayashi, Dai Yamamoto, Motozumi Matsui, Tomas J AcostaAbstract:Abstract Prostaglandin F2α (PGF 2α ) is the primary luteolysin in the cow. During the early luteal phase, the Corpus Luteum (CL) is resistant to the luteolytic effect of PGF 2α . Once mature, the CL becomes responsive to PGF 2α and undergoes luteal regression. These actions of PGF 2α coincide with changes in luteal blood flow (BF): PGF 2α has no effect on BF in the early CL, but acutely increases BF in the peripheral vasculature of the mature CL within 30min of PGF 2α injection. During spontaneous luteolysis, luteal BF increases on Days 17–18 of the estrous cycle, prior to any decrease in plasma progesterone (P). The increase in luteal BF is synchronous with an increase in plasma PGFM levels, suggesting that pulsatile release of PGF 2α from uterus stimulates the increase in luteal BF. Serial biopsies of these CL showed that mRNA expression for endothelial nitric oxide synthase (eNOS) together with endothelin-1 (ET-1) and angiotensin converting enzyme (ACE) increases on Days 17–18 when the luteal BF is elevated. On Day 19 when plasma P level firstly decreases, eNOS mRNA returns to the basal level whereas ET-1 and ACE mRNA remains elevated. Cyclooxygenase-2 (COX-2) mRNA expression increases on Day 19. In support of these data, an in vivo microdialysis study revealed that luteal ET-1 and angiotensin II (Ang II) secretion increases and precedes PGF 2α secretion during spontaneous luteolysis. In conclusion, we show for the first time that an acute increase of BF occurs in the peripheral vasculature of the mature CL together with increases in eNOS expression and ET-1 and Ang II secretion in the CL during the early stages of luteolysis in the cow. We propose that the increase in luteal BF may be induced by NO from large arterioles surrounding the CL, and simultaneously uterine or exogenous PGF 2α directly increases ET-1 and Ang II secretion from endothelial cells of microcapillary vessels within the CL, thereby suppressing P secretion by luteal cells. Taken together, our results indicate that an acute increase in luteal BF occurs as a first step of luteolysis in response to PGF 2α . Therefore, local BF plays a key role to initiate luteal regression in the cow.
P Devroey - One of the best experts on this subject based on the ideXlab platform.
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GnRH-agonist/HMG treatment for superovulation in IVFor GIFT
2016Co-Authors: J. Smitz, P Devroey, M Camus, J Deschacht, I Khan, C Staessen, L Van Waesberghe, A Wisanto, A. C. Van SteirteghemAbstract:'To whom correspondence should be addressed Endometrial biopsies showing Inadequate development were observed after ovarian stimulation with the GnRH agonist Buserelin and HMG for IVF or GIFT when luteal supple-mentation was omitted. Ninety-one patients were randomly allocated to two luteal supplementation regimens: in 41 women HCG and hi 50 women progesterone and oestradiol valerate. The pregnancy rate was similar for both supplemen-tation regimens. In pregnant patients treated with a combina-tion of the GnRH agonist and HMG a delay of implantation of 1.3 days was observed compared to pregnancies after domiphene citrate-HMG stimulation. This delay was not due to slower preimplantation embryo development after GnRH agonist-HMG treatment. Temporarily defective Function of the Corpus Luteum was evidenced by measuring serum pro-gesterone, 17/3-oestradiol and 17-hydroxyprogesterone hi the patients receiving progesterone and oestradiol valerate. This inadequate Corpus Luteum Function could be related to the prolonged blockage of pituitary gonadotrophic Function after arrest of the GnRH agonist. Key words: luteal phase/GnRH agonist/IVF/GIF
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the early luteal phase administration of estrogen and progesterone does not induce premature luteolysis in normo ovulatory women
European Journal of Endocrinology, 2006Co-Authors: Nicole G M Beckers, Nick S. Macklon, P Devroey, Peter Platteau, Marinus J C Eijkemans, Frank H De Jong, Bart C J M FauserAbstract:Objective: The luteal phase after ovarian hyperstimulation for in vitro fertilization (IVF) is insufficient. Therefore, luteal phase supplementation is routinely applied in IVF. It may be postulated that premature luteolysis after ovarian hyperstimulation is due to supraphysiological steroid levels in the early luteal phase. In the present study, high doses of steroids are administered after the LH surge in normo-ovulatory volunteers in order to investigate whether this intervention gives rise to endocrine changes and a shortening of the luteal phase. Design: Randomized controlled trial. Methods: Forty non-smoking, normal weight women, between 18 and 37 years of age, with a regular menstrual cycle (24–35 days), received either high dosages of estradiol (E2), progesterone (P), E2CPor no medication. Blood sampling was performed every other day from the day of the LH surge until LHC 14. Duration of the luteal phase and endocrine profiles were the main study outcomes. Results: Early luteal phase steroid concentrations achieved by exogenous administration were comparable with levels observed following ovarian hyperstimulation for IVF. No difference in the luteal phase length was observed comparing all groups. However, a significant decrease in LH levels could be observed 6 days after the mid-cycle LH surge (P!0.001) in women receiving P, resulting in accelerated decrease of inhibin A production by the Corpus Luteum (PZ0.001). Conclusion: The present intervention of high-dose steroid administration shortly after the LH surge failed to induce a premature luteolysis regularly in cyclic women. It seems that the induced transient suppression in LH allowed for a timely recovery of Corpus Luteum Function. Other additional factors may be held responsible for the distinct reduction in luteal phase length observed after ovarian hyperstimulation for IVF.
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reproductive biology and ivf ovarian stimulation and luteal phase consequences
Trends in Endocrinology and Metabolism, 2003Co-Authors: B C Fauser, P DevroeyAbstract:Most clinicians working in in vitro fertilization (IVF) centers worldwide have taken for granted for more than a decade the paradigm of so-called 'controlled' ovarian hyperstimulation, using maximum stimulation by exogenous gonadotropins, together with the gonadotropin-releasing hormone (GnRH) agonist long-protocol. Potential detrimental effects of this approach with regard to oocyte quality, Corpus Luteum Function and endometrial receptivity have been largely ignored. These factors might by themselves have a major impact on IVF outcome and should therefore be considered seriously. The recent introduction of GnRH antagonists along with the current emphasis on the need for transfer of a reduced number of embryos enables a careful re-evaluation of current IVF strategies. We can now render stimulation protocols simpler, starting with a spontaneous menstrual cycle, allowing for more subtle interference with single dominant follicle selection. Here, we discuss recent approaches to ovarian stimulation, the induction of oocyte maturation, and effects of these altered follicular phase interventions on Corpus Luteum Function following ovarian stimulation.
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impact of ovarian stimulation on Corpus Luteum Function and embryonic implantation
Journal of Reproductive Immunology, 2002Co-Authors: Asimina Tavaniotou, Carola Albano, Johan Smitz, P DevroeyAbstract:Abstract The luteal phase has been found to be defective in virtually all the stimulation protocols used in in-vitro fertilization (IVF), indicating that common mechanisms might be involved despite the use of different drugs. A normal luteal phase is characterised by a normal hormonal environment, normal progesterone secretion by the Corpus Luteum and adequate endometrial secretory transformation. Luteinizing hormone supports the Corpus Luteum and luteal luteinizing hormone (LH) levels have been found to be reduced in human menopausal gonadotrophin (HMG), gonadotrophin-releasing hormone (GnRH)-agonist/HMG and GnRH-antagonist/HMG protocols, probably leading to an insufficient Corpus Luteum Function. Supraphysiological steroid serum concentrations routinely observed in stimulated cycles may adversely affect LH secretion and induce a luteal-phase defect. In turn, these high steroid serum concentrations may advance early luteal-phase endometrial development leading to embryo–endometrial asynchrony and decreased pregnancy rates in IVF cycles.
Bajram Berisha - One of the best experts on this subject based on the ideXlab platform.
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expression pattern of hif1alpha and vasohibins during follicle maturation and Corpus Luteum Function in the bovine ovary
Reproduction in Domestic Animals, 2017Co-Authors: Bajram Berisha, Dieter Schams, Daniela Rodler, Fred Sinowatz, Michael W PfafflAbstract:Contents The aim of this study was to characterize expression patterns of hypoxia-inducible factor-1alpha (HIF1A) and vasohibin family members (VASH1 and VASH2) during different stages of ovarian Function in cow. Experiment 1: Antral follicle classification occurred by follicle size and estradiol-17beta (E2) concentration in the follicular fluid into 5 groups ( 180 E2 ng/ml). Experiment 2: Corpora lutea (CL) were assigned to the following stages: days 1–2, 3–4, 5–7, 8–12, 13–16 and >18 (after regression) of oestrous cycle and of pregnancy (months 1–2, 3–4, 6–7, >8). Experiment 3: Cows on days 8–12 were injected with a prostaglandin F2alpha (PGF) analogue and CL were collected before and 0.5, 2, 4, 12, 24, 48 and 64 hr after PGF injection. Expression of mRNA was measured by qPCR, steroid hormone concentration by EIA and localization by immunohistochemistry. HIF1A mRNA expression in our study increases significantly in follicles during final maturation. The highest HIF1A mRNA expression was detected during the early luteal phase, followed by a significant decrease afterwards. In contrast, the mRNA of vasohibins in small follicle was high, followed by a continuous and significant downregulation in preovulatory follicles. The obtained results show a remarkable inverse expression and localization pattern of HIF1A and vasohibins during different stages of ovarian Function in cow. These results lead to the assumption that the examined factors are involved in the local mechanisms regulating angiogenesis and that the interactions between proangiogenic (HIF1A) and antiangiogenic (vasohibins) factors impact all stages of bovine ovary Function.
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effect of prostaglandin f2 alpha on local luteotropic and angiogenic factors during induced Functional luteolysis in the bovine Corpus Luteum
Biology of Reproduction, 2010Co-Authors: Bajram Berisha, H H D Meyer, Dieter SchamsAbstract:The essential role of endometrial prostaglandin F2 alpha (PTGF) for induction of the Corpus Luteum (CL) regression is well documented in the cow. However, the acute effects of PTGF on known local luteotropic factors (oxytocin [OXT] and its receptor, insulin-like growth factor [IGF] 1, and progesterone and its receptor), the principal angiogenic factor vascular endothelial growth factor (VEGF) A and the capillary destabilization factor angiopoietin (ANGPT) 2 were not thoroughly studied in detail. The aim of this study was therefore to evaluate the tissue concentration of these factors during PTGF induced luteolysis. In addition the mRNA expression of progesterone receptor (PGR), OXT receptor (OXTR), IGF1, IGFBP1, ANGPT1, and ANGPT2 was determined at different times after PTGF treatment. Cows (n ¼ 5 per group) in the mid-luteal phase (Days 8–12, control group) were injected with the PTGF analog (cloprostenol), and CL were collected by transvaginal ovariectomy at 0.5, 2, 4, 12, 24, 48, and 64 h after injection. The mRNA expression was analyzed by quantitative real-time PCR, and the protein concentration was evaluated by enzyme immunoassay or radioimmunoassay. Progesterone concentrations, as well as mRNA expression of PGR, in CL tissue were significantly downregulated by 12 h after PTGF. Tissue OXT peptide and OXTR mRNA decreased significantly after 2 h, followed by a continuous decrease of OXT mRNA. IGF1 and VEGFA protein already decreased after 0.5 h. By contrast, the IGFBP1 mRNA was up-regulated significantly after 2 h to a high plateau. ANGPT2 protein and mRNA significantly increased during the first 2 h, followed by a steep decrease after 4 h. The acute decrease of local luteotropic activity and acute changes of ANGPT2 and VEGFA suggest that modulation of vascular stability may be a key component in the cascade of events leading to Functional luteolysis. angiogenic factors, Corpus Luteum Function, gene regulation, luteolysis, luteotropic factors
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effect of prostaglandin f2 alpha on local luteotropic and angiogenic factors during induced Functional luteolysis in the bovine Corpus Luteum
Biology of Reproduction, 2010Co-Authors: Bajram Berisha, H H D Meyer, Dieter SchamsAbstract:The essential role of endometrial prostaglandin F2 alpha (PTGF) for induction of the Corpus Luteum (CL) regression is well documented in the cow. However, the acute effects of PTGF on known local luteotropic factors (oxytocin [OXT] and its receptor, insulin-like growth factor [IGF] 1, and progesterone and its receptor), the principal angiogenic factor vascular endothelial growth factor (VEGF) A and the capillary destabilization factor angiopoietin (ANGPT) 2 were not thoroughly studied in detail. The aim of this study was therefore to evaluate the tissue concentration of these factors during PTGF induced luteolysis. In addition the mRNA expression of progesterone receptor (PGR), OXT receptor (OXTR), IGF1, IGFBP1, ANGPT1, and ANGPT2 was determined at different times after PTGF treatment. Cows (n ¼ 5 per group) in the mid-luteal phase (Days 8–12, control group) were injected with the PTGF analog (cloprostenol), and CL were collected by transvaginal ovariectomy at 0.5, 2, 4, 12, 24, 48, and 64 h after injection. The mRNA expression was analyzed by quantitative real-time PCR, and the protein concentration was evaluated by enzyme immunoassay or radioimmunoassay. Progesterone concentrations, as well as mRNA expression of PGR, in CL tissue were significantly downregulated by 12 h after PTGF. Tissue OXT peptide and OXTR mRNA decreased significantly after 2 h, followed by a continuous decrease of OXT mRNA. IGF1 and VEGFA protein already decreased after 0.5 h. By contrast, the IGFBP1 mRNA was up-regulated significantly after 2 h to a high plateau. ANGPT2 protein and mRNA significantly increased during the first 2 h, followed by a steep decrease after 4 h. The acute decrease of local luteotropic activity and acute changes of ANGPT2 and VEGFA suggest that modulation of vascular stability may be a key component in the cascade of events leading to Functional luteolysis. angiogenic factors, Corpus Luteum Function, gene regulation, luteolysis, luteotropic factors
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regulation of Corpus Luteum Function in cattle an overview
Reproduction in Domestic Animals, 2004Co-Authors: Dieter Schams, Bajram BerishaAbstract:Contents The Corpus Luteum (CL) is a transient reproductive gland that produces progesterone (P), required for the establishment and maintenance of pregnancy. Although the regulation of bovine luteal Function has been studied for several decades, many of the regulatory mechanisms involved are incompletely understood. We are far from understanding how these complex mechanisms Function in unison. The purpose of this overview is to stress important steps of regulation during the lifetime of CL. In the first part, the importance and regulation of angiogenesis and blood flow during CL formation is described. The results underline the importance of growth factors especially of vascular endothelial growth factor A (VEGF A) and basic fibroblast growth factor (FGF-2) for development and completion of a dense network of capillaries. In the second part, the regulation of Function by endocrine/paracrine- and autocrine-acting regulators is discussed. There is now more evidence that besides the main endocrine hormones LH and GH local regulators as growth factors, peptides, steroids and prostaglandins are important modulators of luteal Function. During early CL development until mid-luteal stage oxytocin, prostaglandins and P itself stimulate luteal cell proliferation and Function supported by the luteotropic action of a number of growth factors. The still high mRNA expression, protein concentration and localization of growth factors [VEGF, FGF-1, FGF-2, insulin-like growth factors (IGFs)] in the cytoplasm of luteal cells during mid-luteal stage suggest maintenance (survival) Functions for growth factors. In the absence of pregnancy regression (luteolysis) of CL occurs. Progesterone itself regulates the length of the oestrous cycle by influencing the timing of the luteolytic signal prostaglandin F2α (PGF2α) from the endometrium. The cascade of mediators afterwards is very complex and still not well-elucidated. Evidence is given for participation of blood flow, inflammatory cytokines, vasoactive peptides (angiotensin II and endothelin-1), reactive oxygen species, angiogenic growth factors (VEGFs, FGFs, IGFs) and decrease of the classical luteotropic components as LH-R, GH-R, P450scc and 3β-HSD. Despite of differences in methodology and interpretations, progress has been made and will continue to be made.
Talia Eldargeva - One of the best experts on this subject based on the ideXlab platform.
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serum inhibin a vegf and tnfα levels after triggering oocyte maturation with gnrh agonist compared with hcg in women with polycystic ovaries undergoing ivf treatment a prospective randomized trial
Human Reproduction, 2006Co-Authors: Rachel Babayof, Ehud J Margalioth, Mahmoud Huleihel, Alaa Amash, Edit Zylberharan, Michael Gal, Baruch Brooks, Tzvia Mimoni, Talia EldargevaAbstract:BACKGROUND We aimed to examine the serum levels of inhibin A, vascular endothelial growth factor (VEGF), tumour necrosis factor alpha (TNFalpha), estradiol (E2) and progesterone levels after triggering of final oocyte maturation with GnRH agonist compared with HCG in patients with polycystic ovaries (PCO) and to investigate the relationship between these markers and ovarian hyperstimulation syndrome (OHSS). METHODS Twenty-eight patients with PCO, undergoing controlled ovarian hyperstimulation with FSH and GnRH antagonist for IVF-embryo transfer treatment, were randomized for triggering of final oocyte maturation with GnRH agonist (GnRH agonist group, n = 15) or HCG (HCG group, n = 13). Blood samples were obtained on the day of randomization and thereafter every 2-7 days. Serum levels of inhibin A, VEGF, TNFalpha, E2 and progesterone, the incidence of OHSS, ovarian size and pelvic fluid accumulation were evaluated. RESULTS Serum inhibin A, E2 and progesterone levels were significantly lower in the GnRH agonist group compared with the HCG group, particularly on the day of embryo transfer (P < 0.0001). Serum VEGF and TNFalpha levels were similar between the two groups. Four patients in the HCG group developed severe OHSS, whereas no patient had any symptoms or signs of OHSS in the GnRH-agonist group (P < 0.05). CONCLUSIONS In patients with PCO treated with FSH/GnRH antagonist, final oocyte maturation with GnRH agonist instead of HCG reduces significantly inhibin A, E2 and progesterone levels during the luteal phase. This phenomenon reflects the inhibition of the Corpus Luteum Function and may explain, at least in part, the mechanism of OHSS prevention in high-risk patients. Our results do not support a crucial role for VEGF or TNFalpha in OHSS.
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lower levels of inhibin a and pro αc during the luteal phase after triggering oocyte maturation with a gonadotropin releasing hormone agonist versus human chorionic gonadotropin
Fertility and Sterility, 2003Co-Authors: Ori Nevo, Talia Eldargeva, Shahar Kol, Joseph ItskovitzeldorAbstract:Abstract Objective To investigate the effect of triggering oocyte maturation with GnRH agonist on Corpus Luteum Function by measuring luteal phase levels of inhibin A and pro-αC. Design Prospective randomized trial. Setting In vitro fertilization (IVF) program at a university hospital. Patient(s) Infertile women undergoing IVF-ET treatment. Intervention(s) Controlled ovarian hyperstimulation with FSH and GnRH antagonist, triggering of final oocyte maturation with either hCG (n = 8) or GnRH agonist (n = 8), IVF-ET, and collection of blood samples every 2–3 days during the luteal phase. Main outcome measure(s) Luteal phase serum levels of inhibin A and pro-αC, P, and E 2 . Result(s) Levels of inhibin A, pro-αC, estrogen, and P were significantly lower from day 4 to day 14 after triggering final oocyte maturation by GnRH agonist compared with hCG. Maximal luteal serum inhibin A and pro-αC levels were 91.5 ± 23.6 and 184.1 ± 23.5 pg/mL in the GnRH agonist–treated women compared with 464.7 ± 209.1 and 7,351.6 ± 934.3 pg/mL in women treated with hCG. Conclusion(s) Triggering final oocyte maturation with GnRH agonist instead of hCG in IVF cycles dramatically decreases luteal levels of inhibins, reflecting significant inhibition of the Corpus Luteum Function. This effect may explain, at least in part, the mechanism of ovarian hyperstimulation syndrome prevention by the use of GnRH agonist.
