1 INSERM U131, Hôpital Antoine Béclère, Clamart, 2 Service de Gynécologie-Obstétrique et Médecine de la Reproduction, Hôpital Antoine Béclère, Clamart, 3 Laboratoire de RadioToxicolgie, CEA/ DSV/ DRR, Bruyères le Chatel and 4 Service d'Oncologie-Radiothérapie, Hôpital Saint-Louis, Paris, France
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Abstract |
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Key words: oocyte donation/pentoxifylline/thin endometrium/tocopherol
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Introduction |
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The incidence of preovulatory endometrial thickness <6 mm during assisted reproductive techniques (ART) is low. It is sometimes an iatrogenic response to the aggression of some medical treatment, such as repeated surgery or radiotherapy, but in most cases the causative agent remains unknown. This thin endometrium, unresponsive to intensive estrogen therapy, is associated with a poor outcome in ART (Alam et al., 1993; Abdalla et al., 1994
, Weckstein et al., 1997
).
The literature on the treatment of thin endometrium is rather sparse. It has often been considered irreversible if unresponsive to high levels of estrogen. Vaginal administration of micronized estradiol, compared with oral treatment, significantly increases the serum estradiol level (279 ± 76 versus 2344 ± 398 pg/ml) and the endometrial estradiol concentration (13 ± 2 versus 918 ± 412 pg/mg protein) (Tourgeman et al., 1999). Micronized estradiol, administered vaginally, has thus been described as the treatment of choice for women who have previously failed to achieve adequate endometrial thickness (Tourgeman et al., 2001
). Low-dose aspirin has been reported to enhance the pregnancy rate of such patients in an intrauterine insemination programme (Hsieh, 2000) and in an oocyte donation programme, although this remains controversial (Weckstein et al., 1997
; Check et al., 1998
). None of these authors, however, has described any change in endometrial thickness with low-dose aspirin. It has been reported (Sher and Fisch, 2000
) that vaginal sildenafil positively affected uterine artery blood flow and endometrial development in four patients.
A combination of pentoxifylline (PTX) and tocopherol (vitamin E) has been reported to be an effective treatment for musculocutaneous radiation-induced fibrosis, both in an experimental model and in humans (Delanian et al., 1999; Lefaix et al., 1999
). According to one report, documented by hysteroscopy, this combined treatment led to complete endometrial healing after radiation-induced abrasion (Letur-Kornisch et al., 2002
). Another recent report describes a significant increase in endometrial thickness in six patients with radiation-induced thin endometrium (from 36 mm), after 12 months of this combined treatment (Delanian et al., 2000). We therefore hypothesized that any thin uterine endometrium, even when the causative agent is unknown, can be treated as iatrogenically induced fibrosis.
Accordingly, we tested this treatment in 18 oocyte recipients whose endometrium remained thin in the late proliferative phase, despite vaginal treatment with micronized estradiol commencing on the first day of the observed cycle. All patients received the combination of PTX and vitamin E for 6 months. We then evaluated the effect on endometrial thickness and the pregnancy and delivery rates.
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Materials and methods |
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Ultrasound assessment
To standardize the data for the endometrial evaluation before and after 6 months of treatment, all patients received micronized estradiol (Provames; Cassenne, Paris, France) (2 mg daily on days 1 to 14, vaginally) before the ultrasound evaluation scheduled on day 14 of the cycle.
All scans were performed by one operator, with a SIEMENS Elegra and a 6.5 MHz transvaginal probe. The uterus was examined systematically. Every time the probe was used, it was covered with coupling gel, inserted into a condom, and recoated with gel before insertion in the vagina. The uterus was viewed in the sagittal plane. Endometrial thickness was defined as the minimum distance between the echogenic interfaces of the myometrium and endometrium measured in the plane through the central longitudinal axis of the uterine body. We noted whether the endometrium was multilayered (hypoechoic inner layer and echogenic outer layer). The probe was then directed into the right vaginal fornix to identify the ascending branch of the uterine artery. A pulsed Doppler gate was placed over the vessel to record the flow velocity waveform. The probe was moved to the left fornix to identify the left uterine artery. Blood flow impedance was expressed as the mean pulsatility index of the right and left uterine arteries.
Statistical analysis
The results were expressed as mean values with their standard deviations. The paired t-test was used to assess the change in the endometrial thickness before and after the combined treatment and the MannWhitney U-test to assess the differences in endometrial thickness and other characteristics of patients who did and did not became pregnant. The statistical assessment used StatView software (Abacus Concepts, Inc., Berkeley, CA, USA). A P-value < 0.05 was considered significant.
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Results |
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The combination of PTX and vitamin E resulted in a significant increase in endometrial thickness (P < 0.001). The mean increase was 1.3 ± 1 mm after 6 months of combined treatment (4.9 ± 0.6 mm before and 6.2 ± 1.4 mm after). An increase in endometrial thickness in response to combined treatment was observed in 13 of 18 patients (72%) and little or no change in five patients (Table II). We observed no significant difference in endometrial thickness between the patients who did and did not become pregnant before (5.3 and 4.7 mm respectively) and after (7.3 and 5.7 mm) combined treatment. Similarly, in both groups, neither blood flow impedance nor endometrial pattern differed significantly before and after. Blood flow impedance was, however, normal before this combined treatment for 13 of the 18 patients.
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Three women did not undergo embryo transfer. One patient divorced before the procedure, and two others had embryos that failed to thaw successfully. Implantation failed in the ten remaining patients after embryo transfer. The pregnancy rate was thus 33% and the delivery rate 27%.
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Discussion |
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Several pieces of biological information suggest some mechanisms by which this combination of PTX and vitamin E has proved useful in treating thin endometrium. It is well documented that aggression to living tissue (i.e. by ionizing radiation, surgery, or chronic infection) produces free radicals that play an important role in the initial damage and in the ensuing inflammatory response that precedes fibrosis, apparently a continuous, self-maintaining local process. Tumour necrosis factor (TNF) increases free-radical leakage from mitochondria and may start this vicious circle in cells that produce TNF (Schulze-Osthoff et al., 1992). TNF-
has been detected in the ovaries (Roby et al., 1990
) and is expressed by all types of endometrial cells (fibroblast, immunocompetent, glandular epithelial and vascular). This expression is cycle-dependent and occurs mainly in the endometrial gland (Hunt et al., 1992
; Philippeaux and Piguet, 1993
; Tabibzadeh et al., 1995
; Von Wolff, 1999). Increased TNF-
expression has been associated with implantation failure (Hazout, 1995
). The beginning of the implantation process can be compared to an inflammation-like reaction that is rapidly down-regulated. An excess of pro-inflammatory cytokine at this stage may have the same deleterious effects on embryo survival as it does on fetal survival in an established pregnancy. Such a phenomenon has been already observed in mice (Chaouat et al., 1995
, 1997
).
PTX, a methylxanthine derivative, is a vasodilating agent that enhances red blood cell deformability, inhibits inflammatory reactions and reduces blood viscosity by inhibiting platelet aggregation. It has therefore been used for the symptomatic treatment of various vascular disorders, including intermittent claudication, ischemic leg ulcers, and peripheral vascular diseases. Most studies of its mechanism have focused on its effect on the production and function of TNF (Samlaska and Windfield, 1994). PTX increases the phagocytic activity of polymorphonuclear leukocytes (PMN) and monocytes, antagonizes TNF-
production and activity and reduces in vitro production of many cytokines, including granulocyte-macrophage colony stimulating factor (GM-CSF) and gamma-interferon (IFN-
). In reproduction, PTX has been reported to decrease the fetal resorption rate significantly in the CBA/JxDBA/2 murine model of spontaneous abortion (Chaouat, 1995). The authors of that study hypothesised that PTX works by reducing local TNF-
production. The establishment of pregnancy has been described as a delicate equilibrium between the Th1 and Th2 cytokines (Wegmann and Guilbert, 1992
): the injection of inflammatory cytokines such as IFN-
and TNF-
can terminate normal pregnancies during early gestation. Mating between CBA/JxDBA/2 mice normally results in a high rate of spontaneous fetal resorption; this fetal loss can be prevented by preconceptional anti-BALB/c alloimmmunisation as well as by a variety of other manouvers, including injection of GM-CSF, IL10, anti-IFN
and PTX (Chaouat et al., 1985
, 1995
).
The physiological role of tocopherol (vitamin E) is to scavenge reactive oxygen species (ROS) at times of oxidative stress, when antioxidant enzymes such as superoxide dismutase (SOD) or catalase are unable to limit the damaging effects of ROS, and thus cannot protect cell membranes against lipid peroxidation. Found mainly in cell membranes, vitamin E is the most important antioxidant protecting membrane phospholipids against oxidative damage. In women, the antioxidant system, like the thioredoxin system, has been reported to change during the menstrual cycle in endometrial glands and stroma (Maruyama, 1997; Stark, 2001): levels are highest in the early secretory phase, that is, during the implantation window. Vascular endothelial damage and oxidative stress appear to be causally related to the pathophysiology of pre-eclampsia, which begins initially as an insufficient trophoblast invasion (Kharb, 2000
). A randomized controlled trial among women at high risk of pre-eclampsia found that a combination of vitamins C and E was effective in reducing its incidence (Chappell et al., 1999
).
The precise mechanism by which the PTX-vitamin E combination interacts with fibrotic tissue is not yet known. In the porcine model of radiation-induced musculocutaneous fibrosis, combined PTX-vitamin E treatment induces a significant decrease in TGF-ß1 levels but paradoxically no change in TNF- levels (Lefaix et al., 1999
).
Five patients did not respond to the treatment. In two patients, the intensity of the uterine aggression (iterative and complicated curettages for one and radiotherapy of 70 gy for the other) may well have totally destroyed any possibility of endometrial regeneration. This might explain the lack of response. The cause of the failure to respond by the other three patients is unknown.
Three patients, two of whom had previously undergone total body irradiation (20 gy), spontaneously became pregnant, despite their documented low ovarian reserve (FSH of 17, 80 and 90 mIU/ml). This fact suggests that the treatment may influence ovarian function. We observed improvement of the endometrial thickness for these three patients and can assume that the general effect of the treatment might also affect ovarian fibrosis, especially in the two patients with previous radiotherapy. We can also suppose that some cases of ovarian failure followand are induced bychronic, severe pelvic inflammation, which the treatment may reduce. The patient spontaneously pregnant after IVF failures had initially enrolled in IVF because of severe pelvic infectious disease. Specific studies are required to evaluate this interesting issue, especially since another study has already reported spontaneous pregnancies despite elevated FSH and advanced age (Check et al., 2000).
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Conclusion |
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Acknowledgements |
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Notes |
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References |
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Alam, V., Bernardini, L., Gonzales, J., Asch, R.H. and Balmaceda, J.P. (1993) A prospective study of echographic endometrial characteristics and pregnancy rates during hormonal replacement cycles. J. Assist. Reprod. Genet., 10, 215219.[ISI][Medline]
Bohrer, M.K., Hock, D.L., Rhoads, G.G. and Kemmann, E. (1996) Sonographic assessment of endometrial pattern and thickness in patients treated with human menopausal gonadotropins. Fertil. Steril., 66, 244247.
Chaouat, G., Kolb, J.P., Kiger, N., Stanislawski, M. and Wegmann, T.G. (1985) Immunologic consequences of vaccination against abortion in mice. J. Immunol., 134, 15941598.
Chaouat, G., Menu, E., Delage, G., Moreau, J.F., Khrishnan, L., Hui, L., Meliani, A.A., Martal, J., Raghupathy, R., Lelaidier, C. and et al. (1995) Immuno-endocrine interactions in early pregnancy. Hum. Reprod., 10, (Suppl, 2), 5559.[ISI][Medline]
Chaouat, G., Tranchot Diallo, J., Volumenie, J.L., Menu, E., Gras, G., Delage, G. and Mognetti, B. (1997) Immune suppression and Th1/Th2 balance in pregnancy revisited: a (very) personal tribute to Tom Wegmann. Am. J. Reprod. Immunol., 37, 427434.[ISI][Medline]
Chappell, L.C., Seed, P.T., Briley, A.L., Kelly, F.J., Lee, R., Hunt, B.J., Parmar, K., Bewley, S.J., Shennan, A.H., Steer, P.J. and Poston, L. (1999) Effect of antioxidants on the occurrence of pre-eclampsia in women at increased risk: a randomised trial. Lancet, 354, 810816.[ISI][Medline]
Check, J.H., Nowroozi, K., Choe, J. and Dietterich, C. (1991) Influence of endometrial thickness and echo patterns on pregnancy rates during in vitro fertilization. Fertil. Steril., 56, 11731175.
Check, J.H., Dietterich, C., Lurie, D., Nazari, A. and Chuong, J. (1998) A matched study to determine whether low-dose aspirin without heparin improves pregnancy rates following frozen embryo transfer and/or affects endometrial sonographic parameters. J. Assist. Reprod. Genet., 15, 579582.[ISI][Medline]
Check, J.H., Check, M.L. and Katsoff, D. (2000) Three pregnancies despite elevated serum FSH and advanced age: case report. Hum. Reprod., 15, 17091712.
Coulam, C.B., Bustillo, M., Soenksen, D.M. and Britten, S. (1994) Ultrasonographic predictors of implantation after assisted reproduction. Fertil. Steril., 62, 10041010.
De Geyter, C., Schmitter, M., De Geyter, M., Nieschlag, E., Holzgreve, W. and Schneider, H.P. (2000) Prospective evaluation of the ultrasound appearance of the endometrium in a cohort of, 1,186 infertile women. Fertil. Steril., 73, 106113.
Delanian S. and Letur-Kornisch, H. (2000) uterine restoration by radiation sequelae regression with combined pentoxifylline-tocopherol: a phase II study. Cancer Radiother., 4, 163.
Delanian, S., Balla-Mekias, S. and Lefaix, J.L. (1999) Striking regression of chronic radiotherapy damage in a clinical trial of combined pentoxifylline and tocopherol. J. Clin. Oncol., 17, 32833290.
Dickey, R.P., Olar, T.T., Curole, D.N., Taylor, S.N. and Rye, P.H. (1992) Endometrial pattern and thickness associated with pregnancy outcome after assisted reproduction technologies. Hum. Reprod., 7, 418421.
Glissant, A., de Mouzon, J. and Frydman, R. (1985) Ultrasound study of the endometrium during in vitro fertilization cycles. Fertil. Steril., 44, 786790.
Gonen, Y. (1991) Ultrasonic evaluation of endometrial growth in women with normal cycles during spontaneous and stimulated cycles. Hum. Reprod., 6, 310311.
Gonen, Y., Casper, R.F., Jacobson, W. and Blankier, J. (1989) Endometrial thickness and growth during ovarian stimulation: a possible predictor of implantation in in vitro fertilization. Fertil. Steril., 52, 446450.
Hazout, A. (1995) Tumor necrosis factor and underlying infection. Contracept. Fertil. Sex, 23, 631634.[ISI][Medline]
Hsieh, Y.Y., Tsai, H.D., Chang, C.C., Lo, H.Y. and Chen, C.L. (2000) Low-dose aspirin for infertile women with thin endometrium receiving intrauterine insemination: a prospective, randomized study. J. Assist. Reprod. Genet., 17, 174177.[ISI][Medline]
Hunt, J.S., Chen, H.L., Hu, X.L. and Tabibzadeh, S. (1992) Tumor necrosis factor-alpha messenger ribonucleic acid and protein in human endometrium. Biol. Reprod., 47, 141147.[Abstract]
Kharb, S. (2000) Vitamin E and C in preeclampsia. Eur. J. Obstet. Gynecol. Reprod. Biol., 93, 3739.[ISI][Medline]
Lefaix, J.L., Delanian, S., Vozenin, M.C., Leplat, J.J., Tricaud, Y. and Martin, M. (1999) Striking regression of subcutaneous fibrosis induced by high doses of gamma rays using a combination of pentoxifylline and alpha-tocopherol: an experimental study. Int. J. Radiat. Oncol. Biol. Phys., 43, 839847.[ISI][Medline]
Letur-Kornisch, H., Guis, F. and Delanian, S. (2002) Complete endometrial healing by reversion of radiation-induced abrasion after combined pentoxifylline-tocopherol. Reprod. Technol., in press.
Maruyama, T., Kitaoka, Y., Sachi, Y., Nakanoin, K., Hirota, K., Shiozawa, T., Yoshimura, Y., Fujii, S. and Yodoi, J. (1997) Thioredoxin expression in the human endometrium during the menstrual cycle. Mol. Hum. Reprod., 3, 989993.
Noyes, R.W. and Rock, J. (1950) Dating the endometrial biopsy. Fertil. Steril., 1, 325.
Philippeaux, M.M. and Piguet, P.F. (1993) Expression of tumor necrosis factor-alpha and its mRNA in the endometrial mucosa during the menstrual cycle. Am. J. Pathol., 143, 480486.[Abstract]
Rabinowitz, R., Laufer, N., Lewin, A., Navot, D., Bar, I., Margalioth, E.J. and Schenker, J.J. (1986) The value of ultrasonographic endometrial measurement in the prediction of pregnancy following in vitro fertilization. Fertil. Steril., 45, 824828.
Roby, K.F., Weed, J., Lyles, R. and Terranova, P.F. (1990) Immunological evidence for a human ovarian tumor necrosis factor-alpha. J. Clin. Endocrinol. Metab., 71, 10961102.[Abstract]
Samlaska, C.P. and Winfield, E.A. (1994) Pentoxifylline. J. Am. Acad. Dermatol., 30, 603621.[ISI][Medline]
Schulze-Osthoff, K., Bakker, A.C., Vanhaesebroeck, B., Beyaert, R., Jacob, W.A. and Fiers, W. (1992) Cytotoxic activity of tumor necrosis factor is mediated by early damage of mitochondrial functions. Evidence for the involvement of mitochondrial radical generation. J. Biol. Chem., 267, 53175323.
Sher, G. and Fisch, J.D. (2000) Vaginal sildenafil (Viagra): a preliminary report of a novel method to improve uterine artery blood flow and endometrial development in patients undergoing IVF. Hum. Reprod., 15, 806809.
Sher, G., Herbert, C., Maassarani, G. and Jacobs, M.H. (1991) Assessment of the late proliferative phase endometrium by ultrasonography in patients undergoing in-vitro fertilization and embryo transfer (IVF/ET) Hum. Reprod., 6, 232237.
Stark, J.M. (2001) Inadequate reducing systems in pre-eclampsia: a complementary role for vitamins C and E with thioredoxin-related activities. BJOG, 108, 339343.[Medline]
Tabibzadeh, S., Zupi, E., Babaknia, A., Liu, R., Marconi, D. and Romanini, C. (1995) Site and menstrual cycle-dependent expression of proteins of the tumour necrosis factor (TNF) receptor family, and BCL-2 oncoprotein and phase-specific production of TNF alpha in human endometrium. Hum. Reprod., 10, 277286.
Tourgeman, D.E., Gentzchein, E., Stanczyk, F.Z. and Paulson, R.J. (1999) Serum and tissue hormone levels of vaginally and orally administered estradiol. Am. J. Obstet. Gynecol., 180, 14801483.[ISI][Medline]
Tourgeman, D.E., Slater, C.C., Stanczyk, F.Z. and Paulson, R.J. (2001) Endocrine and clinical effects of micronized estradiol administered vaginally or orally. Fertil. Steril., 75, 200202.
von Wolff, M., Classen-Linke, I., Heid, D., Krusche, C.A., Beier-Hellwig, K., Karl, C. and Beier, H.M. (1999) Tumour necrosis factor-alpha (TNF-alpha) in human endometrium and uterine secretion: an evaluation by immunohistochemistry, ELISA and semiquantitative RT-PCR. Mol. Hum. Reprod., 5, 146152.
Weckstein, L.N., Jacobson, A., Galen, D., Hampton, K. and Hammel, J. (1997) Low-dose aspirin for oocyte donation recipients with a thin endometrium: prospective, randomized study. Fertil. Steril., 68, 927930.
Wegmann, T.G. and Guilbert, L.J. (1992) Immune signalling at the maternal-fetal interface and trophoblast differentiation. Dev. Comp. Immunol., 16, 425430.[ISI][Medline]
Submitted on September 27, 2001; accepted on December 19, 2001.