P-286 Can laser assisted hatching help implantation of warmed blastocysts in presence of fragmented cells ?

Study question

Does laser assisted hatching (LAH) following warming of blastocysts containing fragmentated cells improves blastocyst expansion and implantation?

Summary answer

The application of LAH does not improve blastocyst expansion and implantation regardless the presence or absence of fragmented cells.

What is known already

The absence of natural hatching is one of the hypotheses of implantation failure after cryopreservation, a process that could lead to hardening of the zona pellucida. Another theory is the fact that cellular fragments inside the zona pellucida, surrounding the trophectoderm, could impairs the exit of the blastocyst through the zona decreasing its chances of implantation. Available data regarding the effect of LAH on blastocysts after vitrification are inconclusive and limited to small samples. Evaluating the effectiveness of LHA performed at the time of blastocyst warming when cellular fragments are present could elucidate its impact on hatching and implantation

Study design, size, duration

A bicentric prospective randomized study including 344 successive FET cycles from January 2020 until March 2021. Patients were enrolled only once in the study. Patients underwent a natural cycle or hormonal replacement treatment for FET. Blastocysts graded ≥ BL3BB (Gardner scoring) underwent artificial collapse and were vitrified on D5 or D6. Only blastocysts surviving post-warming were considered in the analysis. Primary end point was clinical pregnancy rate.

Participants/materials, setting, methods

Patients ≤42 years with ≤3 previous oocyte retrievals scheduled for the first elective single embryo transfer (eSET) with vitrified/warmed blastocysts. Survived blastocysts were randomized immediately after warming to LAH group (n = 172) or to control group (no-LAH, n = 172). Cellular fragmentation was annotated as a percentage of the total volume of the embryo (0%, ≤25%, ≤50%, >50%) and LHA was performed on the opposite side. Embryo expansion was annotated at time of transfer, at 3 hours post-warming.

Main results and the role of chance

Patients age were similar between LHA (33.1±9.3) and controls (34.8±7.5). Patients in LAH and controls had similar pregnancy rates (hCG >100) (46% versus 52%, respectively), CPR (37% versus 36%, respectively) (NS) and miscarriage rates. No difference was observed in CPR in relation to patients age. A significant increase in implantation was observed when blastocyst expansion took place 3 hours after warming, independently whether allocated in LAH (47% versus 17%, p < 0.01) or no-LAH group (51% versus 33%, p < 0.01). LAH did not influence cell expansion (83% in LAH versus 85% in no-LAH), however more blastocysts underwent hatching in LAH group (27% versus 12% in no-LAH, p < 0.06). Significantly more embryos that had hatched in LAH group led to pregnancy compared to no-LHA (83% versus 67%, respectively) (p = 0.05).

Extra-cellular (EC) fragmentation not did not impact implantation in neither of the groups. LAH group had 46% of embryos implanted when absence of fragmentation, 40% when EC was present at ≤ 25%, 58% when EC was present at > 25% (NS). In no-LAH group, 52% of embryos implanted when absence of fragmentation, 49% when EC was present at ≤ 25%, 65% when EC was present at > 25% (NS).

Limitations, reasons for caution

A sample size of 700 blastocysts was first chosen calculating a 10% difference in clinical pregnancy rate (CPR) between LAH-group and no-LAH group. The study was interrupted following this interim analysis. Live birth outcomes should be considered in a further analysis to conclude on the null impact of LHA post-warming.

Wider implications of the findings

This study adds to the evidence of the existence of a limited potential of the application of LAH on vitrified-warmed blastocysts and its impact in terms of clinical pregnancy rates.

Trial registration number

not applicable

Advances in CAR-T Cell Genetic Engineering Strategies to Overcome Hurdles in Solid Tumors Treatment

During this last decade, adoptive transfer of T lymphocytes genetically modified to express chimeric antigen receptors (CARs) emerged as a valuable therapeutic strategy in hematological cancers. However, this immunotherapy has demonstrated limited efficacy in solid tumors. The main obstacle encountered by CAR-T cells in solid malignancies is the immunosuppressive tumor microenvironment (TME). The TME impedes tumor trafficking and penetration of T lymphocytes and installs an immunosuppressive milieu by producing suppressive soluble factors and by overexpressing negative immune checkpoints. In order to overcome these hurdles, new CAR-T cells engineering strategies were designed, to potentiate tumor recognition and infiltration and anti-cancer activity in the hostile TME. In this review, we provide an overview of the major mechanisms used by tumor cells to evade immune defenses and we critically expose the most optimistic engineering strategies to make CAR-T cell therapy a solid option for solid tumors.

Engineering Next-Generation CAR-T Cells for Better Toxicity Management

Immunoadoptive therapy with genetically modified T lymphocytes expressing chimeric antigen receptors (CARs) has revolutionized the treatment of patients with hematologic cancers. Although clinical outcomes in B-cell malignancies are impressive, researchers are seeking to enhance the activity, persistence, and also safety of CAR-T cell therapy-notably with a view to mitigating potentially serious or even life-threatening adverse events like on-target/off-tumor toxicity and (in particular) cytokine release syndrome. A variety of safety strategies have been developed by replacing or adding various components (such as OFF- and ON-switch CARs) or by combining multi-antigen-targeting OR-, AND- and NOT-gate CAR-T cells. This research has laid the foundations for a whole new generation of therapeutic CAR-T cells. Here, we review the most promising CAR-T cell safety strategies and the corresponding preclinical and clinical studies.

Erythropoietin is a major regulator of thrombopoiesis in thrombopoietin-dependent and -independent contexts

Thrombopoietin (TPO), through activation of its cognate receptor Mpl, is the major regulator of platelet production. However, residual platelets observed in TPO- and Mpl-loss-of-function (LOF) mice suggest the existence of an additional factor to TPO in platelet production. As erythropoietin (EPO) exhibited both in vitro megakaryocytic potential, in association with other early-acting cytokines, and in vivo platelet activation activity, we sought to investigate its role in this setting. Here, we used multiple LOF models to decipher the reciprocal role of EPO and TPO in the regulation of platelet production in TPO-LOF and Mpl-LOF mice and of platelet size heterogeneity in wild-type mice. We first identified EPO as the major thrombopoietic factor in the absence of the TPO-Mpl pathway. Based on the study of several mouse models we found that the EPO-EPO receptor pathway acts on late-stage megakaryopoiesis and is responsible for large-sized platelet production, while the TPO-Mpl pathway promotes small-sized platelet production. On the basis of our data, EPO might be used for thrombocytopenia supportive therapy in congenital amegakaryocytopoiesis. Furthermore, as a distribution skewed toward large platelets is an independent risk factor and a poor prognosis indicator in atherothrombosis, the characterization of EPO's role in the production of large-sized platelets, if confirmed in humans, may open new perspectives in the understanding of the role of EPO-induced platelets in atherothrombosis.

How to demonstrate that eSET does not compromise the likelihood of having a baby?

BACKGROUND

In several randomized studies, elective single embryo transfer (eSET) has proven its effectiveness in reducing twin pregnancy rates while obtaining acceptable overall pregnancy rates. However, there is no outcome measurement consensus to evaluate the effectiveness of eSET versus double-embryo transfer (DET).

METHODS

This study evaluated whether or not adopting an eSET strategy instead of a DET strategy lowers the probability of having at least one live-born infant in good prognosis couples. Seven hundred and twenty-six couples were divided into two groups. The retrospective arm of the study was undertaken on the first group of couples (n = 483, DET group) and the prospective arm performed on the second group of couples (n = 243, SET group). In these specific populations, the probability of a woman having at least one live-born infant and the probability that one embryo utilized leads to a child were the main outcome measures.

RESULTS

The probability of a woman having at least one live-born infant was 60.5% in the DET group compared with 60.8% in the SET group. The probability of a live-born child per embryo utilized was not significantly different between the SET and the DET groups, 18.9% and 17.6%, respectively. In addition, the cumulative multiple live birth rate was significantly lower in the SET compared with the DET group.

CONCLUSIONS

In this observational study, using appropriate cryopreservation techniques, the chance of delivering a live baby, per utilized embryo, in an elective SET strategy is as good as that for DET.

Fertilisation and pregnancy outcome after ICSI in globozoospermic patients without assisted oocyte activation

The successful outcome of intracytoplasmic sperm injection (ICSI) with globozoospermic sperm and non-activated oocytes is reported. Three couples underwent ICSI treatment and two of the patients were siblings. Forty-four non-activated oocytes were injected, 26 oocytes fertilised normally and 17 good quality embryos were obtained. Six embryo transfers were carried out, three with fresh embryos and three with frozen-thawed embryos. Three pregnancies resulted from the fresh embryo transfers and additionally two pregnancies were obtained after the transfer of frozen-thawed embryos. Two healthy babies were born. One twin pregnancy is ongoing. Our case reports demonstrate that in some ICSI attempts undertaken with globozoospermic sperm cells from two of our patients, high fertilisation rates, pregnancies and live births can be achieved, without artificially activated oocytes. Our data also suggest that in some cases, round-headed spermatozoa lack the capacity to activate the oocyte. Therefore, it cannot be excluded that artificial oocyte activation could be of help in globozoospermic patients with complete fertilisation failure.

Nonlinear propagation of subpicosecond ultraviolet laser pulses in air

We report filamentation of subpicosecond UV laser pulses with only millijoule energy in atmosphere. The results are in good agreement with a numerical simulation using a quasi-three-dimensional propagation code.

High frequency in esophageal cancers of p53 alterations inactivating the regulation of genes involved in cell cycle and apoptosis

Somatic mutations of the tumor suppressor gene p53 have been frequently detected in esophagal cancers, but their biological significance remains to be established. The tumor suppressor activity of p53 results in part from its ability to transactivate genes involved in the cell cycle and apoptosis, such as p21, bax and PIG3, and some p53 mutations may have a differential effect on the transactivation of these target genes. We developed yeast strains in which the activation by wild-type p53 of reporter plasmids containing p53 binding sites present within these target genes induces a change in the color of the colonies (red/white). Using these strains, we analyzed 56 esophageal cancers from patients residing in Normandy, France, a high incidence geographic area. Forty-seven tumors (84%), scored as mutant with the p21, bax and PIG3 reporter strains and in most of the cases (76%), the percentage of red colonies suggested that both p53 alleles were inactivated. Sequencing analysis allowed the identification of a p53 mutation in each positive sample, and the spectrum of mutations was in agreement with the etiological role of tobacco and alcohol. These results confirm the high frequency of biallelic p53 mutations in esophageal carcinoma and strongly suggest that their biological consequence is the complete alteration of the transactivation of genes involved in the cell cycle and apoptosis, which indicates that p53 alteration is a key event in esophagus carcinogenesis.

Roux-en-Y limb motility after total or distal gastrectomy in symptomatic and asymptomatic patients

BACKGROUND

The aims of this study were to compare Roux-en-Y limb motor patterns after total or distal gastrectomy, and to identify possible motor differences between symptomatic and asymptomatic patients. The usefulness of preoperative recording was also investigated.

STUDY DESIGN

Sixteen patients were enrolled in the study, 10 patients after total gastrectomy (TG group) and 6 patients after distal gastrectomy (DG group). In 6 of 10 patients in the TG group, recordings were obtained before and after operation. Manometric recordings in the limb lasted 6 hours in all patients, 3 hours during fasting, and 3 hours after a 750-kcal meal. An intravenous injection of trimebutine (100-mg i.v.) was systematically administered at the end of each recording session. Motor results of the patients were compared with those obtained in the intact jejunum of 20 healthy controls.

RESULTS

After operation, when patients were compared with controls, phase III (ie, regular activity of the migrating motor complex) was more frequent and more often incompletely propagated (5 of 16 patients versus 1 of 20 controls, unadjusted p < 0.05) and was significantly slower (p < 0.01 versus controls). Intravenous trimebutine induced phase III in 12 of 16 patients within a mean of 8.8 +/- 1 (SEM) minutes, longer than in controls (delay < 2 minutes). The fed pattern was shorter than in controls in both TG and DG groups, and the postprandial area under the curve during successive 30-minute periods was reduced in the DG group compared with controls (p < 0.01). In patients investigated before gastrectomy, motor parameters were not different from those of controls. Surgery resulted in an increased number of phase IIIs and a decreased migration velocity (p < 0.01) of phase III, a longer delay in response after trimebutine (p < 0.0001), and a reduced postprandial motor response (p < 0.01). After the operation, 4 of 10 patients in the TG group and 5 of 6 patients in the DG group were symptomatic. Symptomatic patients had slower and more often incompletely propagated (p < 0.01) phase III compared with asymptomatic patients.

CONCLUSIONS

Roux-en-Y limb reconstruction mainly disturbs phase III propagation and the motor response to a meal. Motor changes are more marked after DG than after TG. Disturbed phase III propagation is the main difference between symptomatic and asymptomatic patients. Successful induction of phase III with trimebutine after gastrectomy and Roux-en-Y reconstruction indicates maintenance of encephalinergic mechanisms.

Formation of a conducting channel in air by self-guided femtosecond laser pulses

We report a drastic reduction of air resistivity following the passage of a self-guided femtosecond pulse from a Ti:sapphire laser system at 800 nm with energies per pulse between 1 and 14 mJ and a pulse duration of 120 fs. Connected plasma filaments with a length that can exceed 150 cm are created by these pulses. The presence of a conducting plasma channel results from multiphoton ionization of air molecules in the filament core.

Postoperative management of stage II/III colon cancer: a decision analysis

BACKGROUND & AIMS

Two separate decisions must be made for the management of patients with resected stage II/III colon cancer: whether to begin adjuvant chemotherapy and whether patients should be included in a follow-up protocol consisting of regular monitoring of carcinoembryonic antigen level and of colonoscopy and imaging. The standard management for these patients is adjuvant chemotherapy for stage III patients and follow-up for stage II/III patients with resected colon cancer.

METHODS

Decision analysis was used to compare the effectiveness (5-year survival rate) and cost-effectiveness ratio of 7 strategies of treatment and follow-up.

RESULTS

The most cost-effective strategies were adjuvant chemotherapy for all patients with stage II/III resected colon cancer, with either no follow-up or follow-up only for patients aged less than 75 years with a seric preoperative carcinoembryonic antigen level of >5 ng/mL (5-year survival, 62.3% or 62.7%; cost per surviving patient, $8254 or $8657, respectively). The order of efficacy of the strategies was insensitive to changes in the values of the studied variables. The method of follow-up does little to improve 5-year survival but adds substantial cost.

CONCLUSIONS

The current standard strategy may not be the most cost-effective strategy for the management of patients with resected colon cancer.

Anomalous long-range propagation of femtosecond laser pulses through air: moving focus or pulse self-guiding?

Self-guided propagation of femtosecond laser pulses is studied for a converging-beam configuration. Channeling of the pulse energy through various gases is observed over distances well beyond the lens focal point, a fact that cannot be explained by the moving-focus model. The results are in good agreement with three-dimensional numerical simulations.

Tracing a Metameric Match to Individual Variations of Colour Vision

A metameric match may be accepted by one observer but rejected by another, indicating that the colour vision of the two observers is different. We analysed the variations of normal colour vision using metameric surfaces. First, we modelled the matches of a theoretical colour-normal observer on the Davidson and Hemmendinger (D&H) colour rule (Kaiser and Hemmendinger, 1980 Color Research and Applications5 65 – 71), using spectroradiometric measurements and a set of fundamentals (Stockman, Macleod, and Johnson, 1993 Journal of the Optical Society of America A10 2491 – 2521). We also derived deviate fundamentals by changing the macular pigment density, the lens density, the photopigment density, and by shifting the long-wave sensitive photopigment. Modelling the deviate normal observer matches yields shifts of no more than 1 sample on the D&H colour rule. The largest shifts are produced by changes in lens density.

Second, we asked six observers to perform a match on the D&H colour rule. We also estimated their macular pigment densities and their lens densities by using heterochromatic flicker photometry matches at 466 nm and 413 nm versus a 558 nm reference, and we recorded their Nagel anomaloscope setting. Then, we computed their personalised fundamentals in order to predict their D&H colour matches. As the most frequent match in a sample of young observers is F-15 and the modelling for the theoretical observer yields G-15, a systematic error occurs in the predictions. After correction for this error, the results show that the metameric match of five out of six observers is better predicted by using the personalised correction of the lens and macular pigment optical density only, than by using the theoretical colour observer data.

Brightness matching and flicker photometric data obtained over the full mesopic range

Three normal observers made visual matches from 0.03 to 100 td on a 10 degree central field at 445, 560 and 630 nm, using two different methods: heterochromatic flicker photometry and direct comparison brightness matching. In a relative sensitivity vs illuminance plot, the brightness matches underwent smooth changes, while the flicker curve exhibited a step-like transition around 1 td, between two separate branches. A reverse Purkinje shift was found on the high mesopic branch at 630 nm, possibly due to cone-cone interactions, and on the low mesopic branch at 445 nm, with questionable origin. At 630 nm and 0.03 td, both methods yielded matches that were not truly scotopic but might not have addressed the same mechanisms.