Is there a risk of cytomegalovirus transmission during in vitro fertilization with donated oocytes?

Presence of hepatitis B virus in oocytes and embryos: a risk of hepatitis B virus transmission during in vitro fertilization

OBJECTIVE

To define the risk of hepatitis B virus (HBV) transmission through oocytes and embryos from chronic HBV carriers.

DESIGN

Laboratory-based study.

SETTING

Research laboratory in a university hospital.

PATIENT(S)

Thirty-one couples with hepatitis B surface antigen (HBsAg)-negative women and HBsAg-positive men, 41 couples with HBsAg-positive women and HBsAg-negative men, and 39 seronegative couples.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Hepatitis B virus DNA and RNA analyses in oocytes and embryos, and the location of virus particles containing HBsAgs.

RESULT(S)

Hepatitis B virus DNA was detected in 3 of 18 male HBsAg-positive/female HBsAg-negative couples (and in 13 of 84 embryos) and 3 of 14 male HBsAg-negative/female HBsAg-positive couples (and in 15 of 71 oocytes and embryos). Hepatitis B virus RNA was detected in 9 of 13 male HBsAg-positive/female HBsAg-negative couples (and in 39 of 52 embryos) and 8 of 17 male HBsAg-negative/female HBsAg-positive couples (and in 30 of 63 oocytes and embryos). The HBsAg, which is present in the nuclei and cytoplasm of oocytes and embryos, was detected in 6 of 10 male HBsAg-negative/female HBsAg-positive couples (and in 13 of 20 oocytes and embryos). Hepatitis B virus DNA, HBV RNA, and HBsAg were not found in 135 oocytes and embryos from 39 seronegative couples.

CONCLUSION(S)

The presence of HBV in oocytes and embryos suggests the possibility of vertical transmission of HBV via the germ line.

Human cytomegalovirus seroprevalence and risk of seroconversion in a fertility clinic population

OBJECTIVE

To retrospectively evaluate factors influencing human cytomegalovirus serologic status of couples consulting our fertility clinic.

METHODS

Human cytomegalovirus individual serologic status of 3,227 women and 2,565 men was studied according to age, serologic status of the sexual partner, and presence of children in the family at entry in the clinic. Among 1,906 initially seronegative individuals, human cytomegalovirus seroconversions during follow-up were recorded and correlated to age, serologic status of the sexual partner, and presence of children aged younger than 3 years in the family.

RESULTS

Human cytomegalovirus status at entry in the fertility clinic depended on age, but women were more frequently seropositive (54%) than men (43%), although they were younger (mean age 33 years for women and 37 years for men). The probability of seroconversion of women and men was significantly associated with the presence of children aged younger than 3 years; 35 of 217 women (16%) and 17 of 130 men (13%) living with children aged younger than 3 years seroconverted compared with 37 of 1,066 women (3.4%) and 16 of 493 men (3.2%) without children. Moreover, women's seroconversion was significantly associated with the seropositivity of the sex partner; 13 of 96 (13.5%) women with a cytomegalovirus seropositive partner seroconverted compared with 33 of 452 (7.3%) of those without such a partner.

CONCLUSION

Our results suggest that human cytomegalovirus is sexually transmitted among couples in our fertility clinic. Safe sex practices should be included in hygiene precaution advice given to pregnant women to avoid human cytomegalovirus contamination.

LEVEL OF EVIDENCE

II.

The effects of murine cytomegalovirus on the maturation, fertilization, cleavage and blastula formation of mouse oocytes in vitro

To study the effects of mouse cytomegalovirus (MCMV) on the in vitro maturation, fertilization, cleavage and blastula formation of mouse oocytes, the immature oocytes were infected in vitro by MCMVs of different dosages (100 TCID(50), 10 TCID(50) and 1 TCID(50)). The oocytes were then observed for in vitro maturation, fertilization, cleavage and blastula formation and the ultrastructural changes after the culture with the viruses. Our results showed that no significant differences were found in IVM, IVF, cleavage and blastula formation among the groups treated with of virus of various dosages. And ultrastructural abnormality was observed in the oocytes treated by 100 TCID(50) of viruses. It is concluded that MCMV did not have any conspicuous effects on IVM, IVF, cleavage and blastula formation of murine immature oocytes.

Disinfection procedures for controlling microorganisms in the semen and embryos of humans and farm animals

Semen and embryos generated by assisted reproductive techniques (ARTs) may be contaminated with numerous microorganisms. Contamination may arise from systemic or local reproductive tract infections in donors or the inadvertent introduction of microorganisms during ARTs, and may lead to disease transmission. This review describes sanitary procedures which have been investigated to ascertain whether they are effective in rendering semen and embryos free of pathogenic microorganisms, including internationally adopted washing procedures, which can be supplemented by antibiotics and enzymatic treatments. Other methods include treatment with antibodies or ozone, photoinactivation, acidification, and the use of novel antiviral compounds. In conclusion, despite the wide range of antimicrobial procedures available, none can be recommended as a universal disinfection method for rendering semen and embryos free from all potentially pathogenic microorganisms. However, some procedures are unsuitable, as they can compromise the viability of semen or embryos. In humans, washing by the gradient centrifugation method appears to be effective for reducing the microbial population in semen and is harmless to the spermatozoa. A useful procedure for embryos involving multiple washes in sterile medium has much to commend it for the prevention of disease transmission; furthermore, it is recommended by the International Embryo Transfer Society (IETS).

Transmission virale et assistance médicale à la procréation : le cas des Herpesviridae

Procreation with sperm donation is at present achieved by insemination either in the uterus or in vitro, always from ejaculated and washed spermatozoa. Then, the infectious risk only exists if the donor sperm is capable of transporting the virus or its DNA, either by adhesion or by integration. With CMV, HSV1 and HSV2, medically assisted procreation in couples (AI or IVF-ET) does not increase the risk of viral contamination as compared with natural procreation, except possibly the cases of surgical procedure to pick up testicular sperm to be used in ICSI. Animal experiments show that, even if viral material is introduced in the oocyte, it may be eliminated from the embryo, at least for CMV.

Experimental inoculation of male mice with murine cytomegalovirus and effect on offspring

BACKGROUND

Murine cytomegalovirus (MCMV) was used to examine aspects of viral infection in male mice, and its possible transmission to their offspring.

METHODS AND RESULTS

FVB/N mice inoculated intratesticularly with 5x10(5) plaque forming units (PFU) of MCMV, developed peritoneal haemorrhagic exudates, spleen hypertrophy and acute local infection. Infectiousness was detected until 15 days post-inoculation (D15 PI) in the genital organs, and virus DNA up to D35 PI. Testicular endothelial and Leydig cells were infected, and peritubular cells severely damaged. Spermatogenesis was affected, but neither germ cells nor Sertoli cells were infected. No virus was found in the epididymal epithelial cells. Viral DNA was detected in cells extracted from vas deferens samples until D15 PI. Neither infectious virus nor viral DNA were found in spermatozoa recovered from uterine fluid, fertilized oocytes, blastocysts, fetal tissues or newborn animals following the mating of infected males with uninfected females.

CONCLUSIONS

MCMV harboured in the male genital organs was not transmitted to their offspring, even when mating occurred during the acute phase of CMV disease. Although the infection may have had an impact on spermatogenesis, fertility was not affected. These results do not support the hypothesis of conceptus MCMV infection by the fertilizing spermatozoon in natural conception.

A strategy for rapid cooling of mouse embryos within a double straw to eliminate the risk of contamination during storage in liquid nitrogen

Double packaging, in which an inner straw containing the specimen is inserted into an outer, larger straw (here termed 'straw-in-straw') to prevent the inner straw from coming into direct contact with liquid nitrogen provides a simple strategy for reducing or eliminating the potential contamination risk associated with storage in liquid nitrogen. This approach has in the past been used in conjunction with cryopreservation by slow cooling, but has not previously been tested for use throughout an entire rapid cooling and warming procedure. This study determined whether keeping the straw containing the embryos inside a second protecting container throughout the cryopreservation and storage protocol would compromise embryo viability. We established that a cryoprotectant containing a high polymer concentration (35% dextran or Ficoll) together with 25% ethylene glycol (as the penetrating cryoprotectant) was highly effective for day 2 and day 3 mouse embryos in both single and double straws. The survival and development of all cryopreserved embryos, as assessed both in vitro and in vivo, was not statistically different to their untreated controls. This established that a protein/serum-free cryoprotectant solution supplemented with polymers could provide complete protection of mouse embryos. It also shows, for the first time, that embryos can be cooled by direct immersion in liquid nitrogen and warmed by direct immersion into a waterbath within a double straw arrangement to reduce the likelihood of contamination.