Characterization of Vaccine Breakthrough Cases during Measles Outbreaks in Milan and Surrounding Areas,Italy, 2017–2021

Despite the existence of an effective live-attenuated vaccine, measles can appear in vaccinated individuals. We investigated breakthrough measles cases identified during our surveillance activities within the measles/rubella surveillance network (MoRoNet) in Milan and surrounding areas (Northern Italy). Between 2017 and 2021, we confirmed measles virus (genotypes B3 or D8) infections in 653 patients and 51 of these (7.8%) were vaccinees. Among vaccinated individuals whose serum was available, a secondary failure was evidenced in 69.4% (25/36) of cases while 11 patients (30.6%) were non-responders. Non-responders were more frequently hospitalized and had significantly lower Ct values in both respiratory and urine samples. Median age and time since the last immunization were similar in the two groups. Importantly, we identified onward transmissions from vaccine failure cases. Vaccinees were involved in 20 outbreaks, in 10 of them they were able to transmit the virus, and in 8 of them, they were the index case. Comparing viral hemagglutinin sequences from vaccinated and non-vaccinated subjects did not show a specific mutation pattern. These results suggest that vaccination failure was likely due to the poor immune response of single individuals and highlights the importance of identifying breakthrough cases and characterizing their clinical and virologic profiles.     

Origin of DNA damage in ejaculated human spermatozoa

The molecular basis of many forms of male infertility is poorly defined. One area of research that has been studied intensely is the integrity of the DNA in the nucleus of mature ejaculated spermatozoa. It has been shown that, in men with abnormal sperm parameters, the DNA is more likely to possess strand breaks. However, how and why this DNA damage originates in certain males and how it may influence the genetic project of a mature spermatozoon is unknown. Two theories have been proposed to describe the origin of this DNA damage in mature spermatozoa. The first arises from studies performed in animal models and is linked to the unique manner in which mammalian sperm chromatin is packaged, while the second attributes the nuclear DNA damage in mature spermatozoa to apoptosis. One of the factors implicated in sperm apoptosis is the cell surface protein, Fas. In this review, we discuss the possible origins of DNA damage in ejaculated human spermatozoa, how these spermatozoa arrive in the ejaculate of some men, and what consequences they may have if they succeed in their genetic project.     

A Slight Adjustment of the Nutri-Score Nutrient Profiling System Could Help to Better Reflect the European Dietary Guidelines Regarding Nuts

The consumption of nuts remains low among European populations despite widespread inclusion as a recommended food group across European dietary guidelines. Front-of-Pack nutrition labelling systems are designed to support consumers make healthier choices and to stimulate product improvement, thus representing a pivotal opportunity to reduce the gap between intakes and recommendations. This study examined how the Nutri-Score algorithm treats nuts and nut-containing products and tested whether slight adjustments could better recognise and motivate nut inclusion in foods and diets. The nutritional score (ScN) and corresponding Nutri-Score letter of 68 nuts and nut-containing products were calculated, using the initial algorithm and slight adjustments, where nut weight was doubled (S1), saturated fats (S2) or energy (S3) from nuts were discounted, or saturated fats were replaced by the saturated fats/lipid ratio (S4). The correlation between the nuts’ content and the ScN was moderate for the initial algorithm (R² = 0.34) and S1 (R² = 0.36), but improved for S2, S3 and S4 (R² = 0.54, 0.55 and 0.52, respectively). Four plain nuts, initially labelled as “B” or “C” obtained a Nutri-Score “A” with S2, S3 and S4. Slight adjustments could better align the Nutri-Score with food-based dietary guidelines, reassure consumers on healthfulness of nuts and nut-containing products, whilst incentivising the inclusion of nuts in diverse foods.     

Antibodies to trophoblast antigens HLA-G, placenta growth factor, and neuroD2 do not improve detection of circulating trophoblast cells in maternal blood

OBJECTIVES: Non-invasive prenatal diagnosis using circulating fetal trophoblast cells has been challenging due to lack of a reproducible trophoblast-specific antibody. We investigated the use of three trophoblast cell-specific antibodies, HLA-G, placenta growth factor, and neuroD2, for the isolation of trophoblast cells from the maternal circulation. METHODS: Trophoblast cells were isolated by density centrifugation from maternal blood samples (gestational age 10-20 weeks, n = 9). All women were carrying a male fetus. Following immunocytochemical staining with the trophoblast-specific antibodies, fluorescent in situ hybridization was performed, to verify whether any stained cells were indeed fetal. RESULTS: The HLA-G antibody had a ubiquitous staining pattern, which was not specific for trophoblast cells. Neither the placenta growth factor nor the neuroD2 antibodies were able to identify any trophoblast cells. Following fluorescent in situ hybridization, no male cells were detected on any of the slides. CONCLUSION: The antibodies used in this study were unable to improve detection of trophoblast cells in the maternal circulation.     

Differential sucrose concentration during dehydration (0.2 mol/l) and rehydration (0.3 mol/l) increases the implantation rate of frozen human oocytes

Novel protocols have increased survival and fertilization rates of cryopreserved oocytes. Nevertheless, in most cases clinical experiences have been disappointing or contradictory. Human oocytes of 141 patients were cryopreserved using a modified slow-cooling protocol involving 1.5 mol/l propane-1,2-diol (PrOH) and 0.2 mol/l sucrose during dehydration, while rehydration was conducted applying decreasing concentrations of PrOH and 0.3 mol/l sucrose. One thousand and eighty-three oocytes were frozen and 403 were thawed, with a survival rate of 75.9%. Among the 306 surviving oocytes, 252 were microinjected and 192 (76.2%) showed two pronuclei. One hundred and eighty zygotes (93.8%) cleaved. The proportion of good quality embryos (grade I and II) was 86.2%. All embryos were transferred and 17 clinical pregnancies were obtained. Pregnancy rates were 21.3% per transfer, 21.8% per patient, and 18.9% per thawing cycle. The implantation rate was 13.5% while the miscarriage rate was 11.8%. To date, four babies have been delivered, while the remaining pregnancies are ongoing. Increased oocyte survival rates can be achieved by moderately high sucrose concentrations in the freezing and thawing solutions. This also ensures elevated success rates in terms of fertilization, embryo development and clinical outcome.     

High rate of biological loss in assisted reproduction: it is in the seed, not in the soil

The vast majority of embryos produced in vitro and transferred fail to develop into an infant, supporting the concept that only a small fraction of embryos is destined to become a live birth. One of the main reasons for such a low embryo-to-infant ratio is the remarkably high number of embryos that after preimplantation genetic diagnosis are found to have a chromosome imbalance. This study reports the overall biological wastage from oocytes inseminated to ongoing pregnancies in patients undergoing preimplantation genetic screening (PGS) because of advanced age, recurrent pregnancy losses or multiple failed IVF cycles. The analysis of biological wastage per oocyte showed that in this cohort of patients, of 333 eggs inseminated, 183 (55.0%) provided embryos for biopsy, and of these, only 33 (18.0% per embryo and 9.9% per oocyte) were normal. A total of 26 embryos were suitable for transfer (14% per embryo and 7.8% per oocyte), but only five (1.5%) implanted and three (1.0%) resulted in live births. In conclusion, there is enormous biological wastage during assisted reproduction, and the data obtained from both embryos and oocytes of patients undergoing PGS support the concept that many embryos and eggs obtained during IVF are intrinsically abnormal and thus fail to implant.     

Molecular methods for selection of the ideal oocyte

Some recent strategies for identifying the ideal oocyte for insemination in assisted reproduction techniques are reviewed. Established methods of assessing the female gamete, such as morphological evaluation of oocytes and cytogenetic analysis of polar bodies using fluorescence in-situ hybridization, will soon be joined by more advanced cytogenetic methods such as the use of comparative genomic hybridization to improve understanding of oocyte genetics. It seems likely, however, that the greatest advances will originate from the evolution of molecular genetic technologies. The application of microarray technology to individual oocytes and their associated cumulus cells has recently been accomplished, providing a simultaneous assessment of activity for thousands of genes and revealing potential viability markers. Furthermore, improved equipment and optimized methods of mass spectrometry have provided sufficient sensitivity to allow proteomic profiles to be generated from single oocytes and embryos, while metabolomic investigations have searched for indicators of oocyte/embryo quality in spent culture medium. Techniques of this type may ultimately lead to non-invasive tests for oocyte quality revealing previously hidden information concerning both oocyte and embryo developmental competence. Once fully validated, these new approaches are expected to revolutionize oocyte and embryo selection, leading to improved implantation rates and higher probabilities of success using elective single embryo transfer.