Reproduktionsmedizin

Since the introduction of in vitro fertilization in 1978, reproductive medicine and its associated scientific fields have developed rapidly. In Germany, progress in this field is impeded by the German Embryo Protection Act. Exemplary are the prohibition of embryo selection and the ban on genetic testing of the pre-implantation embryo. Nevertheless, infertility treatment outcome has to be optimized within the framework of this law, with the aim of making treatment more efficient, lowering the incidence of multiple gestations, making ovarian hyperstimulation safer, as well as reducing the financial costs for the couple.     

Exogenous Modulation of TGF-β1 Influences TGF-βR-III-Associated Vascularization during Wound Healing in Irradiated Tissue

BACKGROUND AND PURPOSE: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial cell carcinomas of the head and neck region, wound-healing disorders occur. Previous experimental studies showed altered expression of transforming growth factor-(TGF-)beta isoforms following surgery in irradiated graft beds. Altered levels of TGF-beta(1) are reported to promote fibrosis and to suppress vascularization during wound healing, whereas expression of TGF-beta receptor-III (TGF-betaR-III) is associated with vascularization. The aim of the study was to analyze the influence of anti-TGF-beta(1) treatment on TGF-betaR-III-associated vascularization in the transition area between irradiated graft bed and graft. MATERIAL AND METHODS: Wistar rats (male, weight 300-500 g) underwent preoperative irradiation of the head and neck region with 40 Gy (four fractions of 10 Gy each; n = 16 animals). A free myocutaneous gracilis flap taken from the groin was then transplanted to the neck in all rats. The time interval between operation and transplantation was 4 weeks. Eight animals received 1 micro g anti-TGF-beta(1) into the graft bed by intradermal injection on days 1-7 after surgery. On days 3, 7, 14, 28, 56, and 120, skin samples were taken from the transition area between transplant and graft bed and from the graft bed itself. Immunohistochemistry was performed using the ABC-POX method to analyze the TGF-betaR-III and E-selectin expression. Histomorphometry was performed to analyze the percentage and the area of positively stained vessels. RESULTS: A significantly higher expression of TGF-betaR-III was seen in the irradiated and anti-TGF-beta(1)-treated graft bed in comparison to the group receiving preoperative irradiation followed by transplantation alone. The percentage of TGF-betaR-III positively staining capillaries from the total amount of capillaries in the anti-TGF-beta(1)-treated graft bed was higher than in the group irradiated only. The total area of capillaries was also higher in the TGF-beta(1)-treated group. CONCLUSION: Neutralizing of TGF-beta(1) activity in irradiated tissue undergoing surgery leads to a higher expression of TGF-betaR-III and increased vascularization. TGF-betaR-III seems to be associated with newly formed blood vessels during neovascularization in wound healing.     

Kryokonservierung und Transplantation von Ovarialgewebe

There are relatively few effective clinical options for preserving female fertility, particularly following aggressive chemotherapy and/or radiotherapy treatment protocols. This document reviews scientific background, current technology, clinical results, and potential future applications of ovarian tissue cryopreservation and transplantation. The technology is investigational although rapidly evolving, and the list of appropriate indications may be expanded in the future. Germany stays abreast of these rapid worldwide developments by having founded the first German network of experts for fertility preservation in patients undergoing chemotherapy and/or radiotherapy.     

A lower ongoing pregnancy rate can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing IVF with GnRH antagonists

BACKGROUND: Eliciting an endogenous LH surge by GnRH-agonist for the induction of final oocyte maturation may be more physiological compared with the administration of HCG. However, the efficacy of this intervention in patients treated for IVF with GnRH antagonists remains to be assessed. METHODS: 106 patients were randomized to receive either 10 000 IU urinary HCG or 0.2 mg Triptorelin for triggering final oocyte maturation. Ovarian stimulation for IVF was performed with a fixed dose of 200 IU recombinant FSH and GnRH antagonist was started on stimulation day 6. Luteal phase was supported with micronized vaginal progesterone and oral estradiol. The study was monitored continuously for safety and stopping rules were established. RESULTS: No significant differences were present in the number of cumulus-oocyte complexes retrieved, in the proportion of metaphase II oocytes, in fertilization rates or in the number and quality of the embryos transferred between the two groups. However, a significantly lower probability of ongoing pregnancy in the GnRH agonist arm prompted discontinuation of the trial, according to the stopping rules established (odds ratio 0.11; 95% confidence interval 0.02-0.52). CONCLUSIONS: Lower probability of ongoing pregnancy can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing ovarian stimulation for IVF with GnRH antagonists.     

Moderne Verfahren der assistierten Reproduktion

Genetic aspects are becoming more and more important in the diagnostics, patient counselling and therapy of assisted reproduction. Compared to spontaneously conceiving patients, genetic disturbances can be found with a higher incidence in patients requiring these techniques, a fact which is not only due to the greater age of such patients. In several cases, genetic disturbances contribute to or even explain infertility. New insights in the field of pharmacogenetics demonstrate that genetic dispositions influence the success of hormonal stimulation. Furthermore, growing knowledge of potential associations between genomic imprinting and assisted reproduction (ART) demands further attention, especially due to the uncovering of new potential risks of ART itself. Performing genetic diagnosis in oocytes or embryos (preimplantation genetic diagnosis, PGD) warrants further evaluation before it becomes a routine technique.     

Generierung und Konservierung von Keimzellen

In vitro maturation (IVM) is a technique which allows the maturation of oocytes from the germinal vesicle stage up to the stage of the fertilization-competent metaphase-II oocytes. Immature oocytes are primarily retrieved from small antral follicles. Their successful maturation is usually documented by formation of the first polar body as an indicator of completion of the first meiotic division. The quality of in vitro matured oocytes can now be judged by polarisation microscopy. This technique allows better quality assessment and is hence a unique instrument for optimising existing IVM protocols. In combination with the now realistic option of successful cryopreservation of mature and immature oocytes by the technique of vitrification, IVM will soon enter new fields of application.     

Analysis of inflammatory periimplant lesions during a 12-week period of undisturbed plaque accumulation—a comparison between flapless and flap surgery in the mini-pig

This study’s aim was to clarify the influence of soft tissue management on the development of periimplant infection. Four weeks after removal of all maxillary premolars in 12 mini-pigs, four BEGO Semados RI implants were inserted in each maxillary quadrant. Employing a split-mouth design, one quadrant was randomized to flapless insertion while the contralateral side was chosen for flap surgery. Following 1, 2, 4 and 12 weeks of transmucosal implant, healing biopsies were retrieved from the periimplant soft tissue and subjected to further analysis. Histomorphometrically, a significant reduction of transmigration of polymorphonuclear neutrophils (week 1, p = 0.007; week 2, p = 0.021; week 4, p = 0.023; week 12, p = 0.013) as well as the density of the subepithelial inflammatory infiltrates (week 1, p = 0.007; week 2, p = 0.046; week 4, p = 0.003; week 12, p = 0.032) was verified following flapless surgery. Quantification of inducible nitric oxide synthase showed significantly reduced expression in the flapless group 2 (p = 0.027), 4 (p = 0.005) and 12 (p = 0.004) weeks post-insertion. Analysis of CD31 and collagen I immunostained sections revealed more regular capillary distribution as well as higher vessel and collagen density in the flapless group. The data of the present study indicate that flapless placement reduces the incidence of inflammatory periimplant soft tissue lesions during a 12-week period. Considering the beneficial effects of flapless placement on early soft tissue healing and stability, the technique might be preferred in case of an uncomplicated locoregional anatomy with sufficient hard and soft tissue. However, this positive effect might disappear after manipulation of the implant and soft tissue during impression taking or try in of the prosthodontic supraconstruction.     

Transconjunctival versus subciliary approach for orbital fracture repair—an anthropometric evaluation of 221 cases

Objectives

In the literature, there is an ongoing discussion about the influence of orbital fractures and the surgical approach on the rate of eyelid deformities of the lower eyelid.

Materials and methods

We present an evaluation of a series of 221 patients 9 months after zygomaticomaxillary complex fracture repair that underwent implant removal. Reference anthropometric data were measured on standardized pre- and postoperative photographs. Analysis included eye fissure width and height, lid sulcus and upper lid height, upper and lower iris coverage, position of cornea to palpebra inferior, canthal tilt, scleral show, ectropion, and entropion. Both operated and contralateral eyelids were evaluated as well as whether a transconjunctival or a subciliary approach was performed.

Results

Time, surgery, and surgical approach presented significant effects on eye fissure index and lower iris coverage. Scleral show was significantly influenced by the surgical procedure itself as well as by the type of incision. The rate of ectropion increased significantly pre- to postoperative.

Conclusions

The subciliary approach included the highest risk of lower lid retraction. The low pre- to postoperative increase of scleral show and ectropion compared to recent studies gives us an idea about the influence of the underlying trauma on the rate of lower lid retraction. The standardized measurements described are accurately and objective to evaluate postoperative results.

Clinical relevance

The transconjunctival approach is preferable in orbital fracture repair.     

Three years of routine vitrification of human zygotes: is it still fair to advocate slow-rate freezing?

Cryopreservation of human oocytes and embryos is a necessary tool in assisted reproduction treatment that leads to an increased cumulative outcome while decreasing costs. Vitrification is a cryopreservation technique that leads to a glass-like solidification, with rapid cooling of cells or tissues. Nowadays vitrification is claimed to be the future of cryopreservation of human embryos due to improved survival rates and clinical outcomes. This study was conducted at a university clinic to assess the safety and efficiency of vitrification of human zygotes as a routine procedure. A total of 849 pronuclear-stage (PN) zygotes were vitrified between March 2004 and July 2006. During this period, 103 cycles of cryopreserved embryo transfer were completed. In total, 339 PN zygotes were thawed resulting in an 89% survival rate (302 PN zygotes). The mean number of embryos per transfer was 2.2. The pregnancy rate obtained was three times higher (36.9%) than that obtained with the slow-rate freezing method (10.2%) used previously in the same centre. In conclusion, vitrification of human zygotes at the pronuclear stage seems to be a successful and reliable method with favourable outcomes and can be recommended as a routine technique for cryopreservation of human embryos.     

Ovarielle Stimulation mit Corifollitropin alfa

Corifollitropin alfa is a new hybrid protein of human follicle-stimulating hormone (FSH) and the C-terminal peptide of the ??-subunit of human chorionic gonadotropin. Due to a slower absorption and a longer terminal half-life, corifollitropin alfa can induce multifollicular development in women undergoing controlled ovarian stimulation using gonadotropin-releasing hormone (GnRH) antagonist-assisted in vitro fertilization (IVF). In two large randomized, double-blind, phase III trials, a single subcutaneous injection of corifollitropin alfa was as effective as 7 daily injections of recombinant FSH in inducing multifollicular development when used as part of a GnRH antagonist protocol. Non-inferiority in ongoing pregnancy rates and numbers of oocytes available for IVF has been established. In another large phase III trial, non-immunogenicity of corifollitropin alfa has been demonstrated.