Pronuclear zygote score following intracytoplasmic injection of hyaluronan-bound spermatozoa: a prospective randomized study

Exploring the Role of Hyaluronic Acid in Reproductive Biology and Beyond: Applications in Assisted Reproduction and Tissue Engineering

Hyaluronic acid (HA) plays a prominent role in various aspects of reproductive biology and assisted reproductive technologies (ART). This review describes the multifaceted influence of HA, ranging from primordial germ cell migration, ovarian follicle development, and ovulation in females to sperm structure, physiology, motility, and capacitation in males. In addition, HA also plays an important role in fertilization and promotes embryo implantation by mediating cellular adhesion and communication within the uterus. Against this physiological background, the review examines the current applications of HA in the context of ART. In addition, the article addresses the emerging field of reproductive tissue engineering, where HA-based hydrogels offer promising perspectives as they can support the development of mature oocytes and spermatogenesis in vitro. Overall, this review highlights the integral role of HA in the intricate mechanisms of reproductive biology and its growing importance for improving ART outcomes and the field of tissue engineering of the reproductive system.

Effects of sperm processing techniques on IVF pregnancy rates: a mini-review

Many factors associated with assisted reproductive technologies significantly influence the success of pregnancy after in vitro fertilization (IVF) either directly or indirectly. These factors include sperm processing techniques, egg retrieval, intrauterine artificial insemination, intracytoplasmic sperm injection, and embryo transfer. Among these technologies, sperm quality is one of the most critical factors for a successful IVF pregnancy. The method used for sperm processing plays a crucial role in determining the quality of sperm. Several widely used sorting techniques, such as conventional swim-up, density gradient centrifugation, magnetic activated cell sorting, and hyaluronic acid, have been extensively compared in various studies. Previous studies have shown that each sperm processing method causes varying degrees of sperm damage, particularly in sperm motility, concentration, morphological features, viability, and DNA integrity. However, sperm processing techniques have been developed slowly, and the impact of these methods on pregnancy rates is still unclear. Further exploration is needed. In this review, we aim to compare the results of different sperm processing techniques concerning sperm quality and IVF pregnancy rates. We will also discuss possible clinical approaches, such as microfluidics and integrated approaches, for testing and improving sperm quality.

The Effect of Sperm DNA Fragmentation on Male Fertility and Strategies for Improvement: A Narrative Review

The inability to conceive due to male infertility is a complex issue with a wide variety of etiologies. Sperm DNA damage can be both a barrier to natural pregnancy and successful assisted reproductive technology (ART). The aim of this narrative review was to describe and highlight the effects of sperm DNA fragmentation and the most recent data on various treatment strategies to decrease sperm DNA damage. Finally, we proposed a management algorithm for couples undergoing ART with increased sperm DNA fragmentation.

Sperm Selection for ICSI: Do We Have a Winner?

In assisted reproductive technology (ART), the aim of sperm cells’ preparation is to select competent spermatozoa with the highest fertilization potential and in this context, the intracytoplasmic sperm injection (ICSI) represents the most applied technique for fertilization. This makes the process of identifying the perfect spermatozoa extremely important. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. Although many studies have been conducted to identify the election technique, many doubts and disagreements still remain. In this review, we will discuss all the sperm cell selection techniques currently available for ICSI, starting from the most basic methodologies and continuing with those techniques suitable for sperm cells with reduced motility. Furthermore, different techniques that exploit some sperm membrane characteristics and the most advanced strategy for sperm selection based on microfluidics, will be examined. Finally, a new sperm selection method based on a micro swim-up directly on the ICSI dish will be analyzed. Eventually, advantages and disadvantages of each technique will be debated, trying to draw reasonable conclusions on their efficacy in order to establish the gold standard method.

Conventional ICSI vs. physiological selection of spermatozoa for ICSI (picsi) in sibling oocytes

BACKGROUND

Physiological selection of spermatozoa for ICSI (PICSI) is a sperm selection method based on sperm binding to hyaluronic acid. Previous studies on the effect of hyaluronic acid binding assays on fertilization and embryo quality have shown inconsistent results. Previous sibling oocyte studies have not found a significant improvement in fertilization or embryo development with hyaluronic acid binding assays.

OBJECTIVE

To compare fertilization and embryo development between standard intracytoplasmic sperm injection (ICSI) and PICSI in sibling oocytes.

MATERIALS AND METHODS

This is a retrospective analysis of all in vitro fertilization (IVF) cycles between January 2017 and April 2020 in which sibling oocytes were randomly fertilized by both ICSI and PICSI. Fertilization rate and the rate of embryos eligible for transfer were compared.

RESULTS

Forty-five IVF cycles, in which 257 oocytes were fertilized with PICSI and 294 with standard ICSI, were compared. Most of the patients included in the study had previous failures of fertilization, poor embryonic development, implantation failure, or miscarriage. All but two of the patients had at least one previous unsuccessful IVF cycle. Both fertilization rates (71% vs. 83%) and transfer eligible embryo rates (38% vs. 51%) were significantly higher in PICSI fertilized oocytes (p = 0.008 and p = 0.01 respectively).

DISCUSSION

Our study is the largest sibling oocyte study comparing ICSI and PICSI, and the first to find a significant improvement in fertilization and embryo quality with PICSI using sibling oocytes. The fact our cohort included almost exclusively couples with previous unsuccessful IVF cycles might suggest that PICSI should be used in selected cases.

CONCLUSION

PICSI improves fertilization rates and transfer eligible embryo rates in sibling oocytes in a selected study group.

Sperm selection methods in the 21st century

Natural sperm selection in humans is a rigorous process resulting in the highest quality sperm reaching, and having an opportunity to fertilize, the oocyte. Relative to other mammalian species, the human ejaculate consists of a heterogeneous pool of sperm, varying in characteristics such as shape, size, and motility. Semen preparation in assisted reproductive technologies (ART) has long been performed using either a simple swim-up method or density gradients. Both methodologies provide highly motile sperm populations; however neither replicates the complex selection processes seen in nature. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. These methods attempt to select a better individual, or population of, spermatozoa when compared to classical methods of preparation. Of the approaches already tested, platforms based upon sperm membrane markers, such as hyaluronan or annexin V, have been used to either select or deselect sperm with varied success. One technology that utilizes the size, motility, and other characteristics of sperm to improve both semen analysis and sperm selection is microfluidics. Here, we sought to review the efficacy of both available and emerging techniques that aim to improve the quality of the sperm pool available for use in ART.

A successful healthy childbirth and an ongoing evolutive pregnancy in a case of partial globozoospermia by hyaluronic acid sperm selection

We here report a successful healthy childbirth and an ongoing evolutive pregnancy in a case of partial globozoospermia after selection of mature spermatozoa bound to hyaluronic acid (HA). The couple underwent two in vitro fertilisation (IVF) cycles. In the first attempt, 14 MII oocytes were retrieved. Randomly, seven oocytes were injected by conventional PVP-ICSI and seven by HA-ICSI. Fertilised oocytes were 2/7 and 4/7 after PVP-ICSI and HA-ICSI respectively. Transfer of two grade A embryos from HA-ICSI lead to birth of a healthy baby. The surplus embryo of the HA-ICSI group was vitrified at blastocyst stage. The two embryos from PVP-ICSI arrested their development. Two years after the childbirth, the vitrified blastocyst was transferred into the uterus, but implant failed. In the second cycle, 14 MII oocytes were retrieved and they were injected by HA-ICSI. Fertilised oocytes were 10 out of 14 injected oocytes. On day 5, two blastocysts were transferred into uterus and a single evolutive pregnancy is ongoing. On day 6, one blastocyst was vitrified. The remaining surplus embryos arrested their development. A healthy childbirth and an ongoing evolutive pregnancy in two consecutive ICSI attempts of the same couple suggest that HA sperm selection might assist in cases with partial globozoospermia.

Physiological ICSI (PICSI) vs. Conventional ICSI in Couples with Male Factor: A Systematic Review

OBJECTIVES

To determine the efficacy of the physiological ICSI technique (PICSI) vs. conventional ICSI in the prognosis of couples, with respect to the following outcome measures: live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage rates.

METHODS

A systematic review of the literature, extracting raw data and performing data analysis. Patient(s): Couples with the male factor, who were subjected to in-vitro fertilization. Main Outcome Measures: rates of live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage.

RESULTS

In the systematic search, we found 2,918 studies and an additional study from other sources; only two studies fulfilled the inclusion criteria for this systematic review. The rates of live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage were similar for both groups.

CONCLUSION

There is no statistically significant difference between PICSI vs. ICSI, for any of the outcomes analyzed in this study. Enough information is still not available to prove the efficacy of the PICSI technique over ICSI in couples with male factor.

Clinical assessment of the male fertility

The evaluation of infertility in males consists of physical examination and semen analyses. Standardized semen analyses depend on the descriptive analysis of sperm motility, morphology, and concentration, with a threshold level that must be surpassed to be considered a fertile spermatozoon. Nonetheless, these conventional parameters are not satisfactory for clinicians since 25% of infertility cases worldwide remain unexplained. Therefore, newer tests methods have been established to investigate sperm physiology and functions by monitoring characteristics such as motility, capacitation, the acrosome reaction, reactive oxygen species, sperm DNA damage, chromatin structure, zona pellucida binding, and sperm-oocyte fusion. After the introduction of intracytoplasmic sperm injection technique, sperm maturity, morphology, and aneuploidy conditions have gotten more attention for investigating unexplained male infertility. In the present article, recent advancements in research regarding the utilization of male fertility prediction tests and their role and accuracy are reviewed.

Hyaluronan-binding system for sperm selection enhances pregnancy rates in ICSI cycles associated with male factor infertility

OBJECTIVES

The aim of the present study was to compare two procedures for sperm selection in ICSI cycles - conventional morphology sperm selection (ICSI-PVP) and chemical selection through Hyaluronan-treated petri dishes (PICSI), when male factor was associated.

METHODS

The evaluated parameters were semen quality, fertilization and cleavage rates, chemical and clinical pregnancy rates, as well as abortion rate. Fifty-six ICSI cycles were included in this report, 19 cycles using PICSI and 37 using conventional ICSI.

RESULTS

PICSI and ICSI showed, respectively, the following outcome: fertilization rates 71.93% (123/171) and 64.14% (127/198); cleavage rates 95.12% (117/123) and 95.27% (121/127); chemical pregnancy rates 63.15% (12/19) and 27.03% (10/37); clinical pregnancy rates 42.10% (8/19) and 16.21% (6/37); and abortion rates 33.33% (4/12) and 40.00% (4/10). According to both Fisher's Exact Test and Chi-square Test, chemical pregnancy (p = 0.05) and clinical pregnancy (p = 0.09) rates were significantly higher in the PICSI group. p values ≤ 0.05 were consider statistically significant.

CONCLUSIONS

The present data indicates that ICSI cycles that used the PICSI technique had a considerably higher chance (≈5 fold) to achieve pregnancy than those who had sperm selected only by morphology assessment. Teratozoospermic patients were those who benefited most with PICSI. Therefore, the technique should be included in laboratory routine with low cost, avoiding the selection of immature sperm with increased rates of peroxidation and DNA fragmentation. Prospective and randomized studies should be applied to strengthen this suggestion.

Hyaluronic Acid Binding Assay Is Highly Sensitive to Select Human Spermatozoa with Good Progressive Motility, Morphology, and Nuclear Maturity

OBJECTIVE

This study was performed to evaluate the correlation of hyaluronic acid binding assay (HBA) with conventional semen parameters, lipid peroxidation (LPO), intracellular reactive oxygen species (ROS), DNA fragmentation (DF), DNA maturity and mitochondrial membrane potential (MMP) level in human spermatozoa.

METHODS

The semen samples were obtained from 98 patients. The seminal plasma was separated for the study of LPO, and the pellet was employed for evaluation of intracellular ROS, DF, nuclear maturity (sperm chromatin structure assay) and MMP through flowcytometry.

RESULTS

The correlation and strength of HBA with respect to the studied parameters were estimated by the Pearson coefficient and multiple liner regression tests. While HBA indicated a positive correlation with progressive motility (β-coefficients = 0.449, p < 0.05) and normal morphology (β-coefficients = 2.722, p < 0.01), it had only negative relationship with DNA integrity (high DNA stain ability; β-coefficients = -0.517, p < 0.05). HBA also did not show any important correlation with other conventional and intracellular sperm parameters.

CONCLUSIONS

The HBA is sensitive to morphological integrity, high progressive motility and nuclear maturation. Nonetheless, HBA is not a reliable test for prediction of sperm intracellular ROS, DF and MMP risks and healthy spermatozoa selection.

Use of hyaluronic acid for sperm immobilisation and selection before intracytoplasmic sperm injection: A systematic review and meta-analysis

AIM: To appraise critically the published randomised controlled trials (RCTs) reporting on the effectiveness of using hyaluronic acid (HA) for sperm immobilisation and selection before intracytoplasmic sperm injection (ICSI).

METHODS: Two authors used the PICO Method in order to perform a comprehensive literature search of the standard medical databases in June 2015. Data from the included studies was extracted independently by two authors using a predefined pro-forma. Review Manager (RevMan) was used to calculate the combined outcomes where multiple studies contributed with their results. Risk ratio (RR) with a 95%CI using the Mantel-Haenszel method was calculated for binary data variables. Heterogeneity was measured using the χ² test and quantified using I². In case of substantial heterogeneity (P < 0.10 for χ² test or I² > 50%) the combined outcome was calculated using the random effects model. The results from the meta-analysis were displayed as forest plots. The guideline of the Cochrane Collaboration was used to assess the risk of bias and it was illustrated as a risk of bias graph.

RESULTS: The systematic literature search identified 166 different studies related to sperm immobilisation and selection for ICSI. Eleven RCTs involving 13719 oocyte intracytoplasmatic injections with sperm immobilised and selected using HA or polyvinylpyrrolidone (PVP) were included in this systematic review and meta-analysis. There was low heterogeneity among the included trials (χ² = 16.86, df = 11, P = 0.11; I² = 35%). There was no statistical difference between HA and PVP groups in terms of fertilisation rate (RR = 1.01; 95%CI: 0.99-1.03; z = 0.75; P = 0.45), good embryos rate (RR = 1.01; 95%CI: 0.96-1.06; z = 0.30; P = 0.76), live birth rate (RR = 1.15; 95%CI: 0.86-1.54; z = 0.92; P = 0.36), clinical pregnancy rate (RR = 1.04; 95%CI: 0.92-1.17; z = 0.62; P = 0.53) and implantation rate (RR = 1.17; 95%CI: 0.94-1.46; z = 0.40; P = 0.16). The quality of most of the included studies was moderate to poor because of unclear randomisation technique, inadequate allocation concealment and blinding.

CONCLUSION: This systematic review and meta-analysis provides evidence of similar efficiency between using HA or PVP for sperm immobilisation and selection before ICSI.

Sperm selection: effect on sperm DNA quality

The selection of spermatozoa without DNA fragmentation and chromosomal diseases prior to assisted reproductive techniques helps to optimize the outcome of the treatment; in particular, sperm selection prior to in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) is crucial. In fact, although ICSI has been successfully and safely applied worldwide for almost 20 years, at the present time we have no real knowledge regarding the hypothetical long-term side effects on ICSI adults, given the increased likelihood of spermatozoa with defective nuclear content fertilizing oocytes.In the case of DNA damage, the basal sperm DNA fragmentation rate can be significantly reduced by some sperm processing procedures that improve the percentage of spermatozoa with normal chromatin structure by filtering out DNA-damaged spermatozoa. After this first step, new advances in micromanipulation can be performed to choose the "ideal" mature spermatozoa for ICSI, reducing potential damage to the gametes. In fact, it is possible to prevent fertilization by DNA-damaged and chromosomal-unbalanced spermatozoa by selecting ICSI sperm by maturation markers such as hyaluronic acid or other zona pellucida receptors. Furthermore, novel noninvasive imaging techniques can be valid tools for helping in the morphological selection of ICSI spermatozoa.

Application of sperm selection using hyaluronic acid binding in intracytoplasmic sperm injection cycles: a sibling oocyte study

The purpose of this study was to investigate whether sperm selection by hyaluronic acid (HA) binding could improve fertilization rate and embryo quality in intracytoplasmic sperm injection (ICSI) cycles. Two hundred nineteen oocytes obtained from eighteen women were injected with either HA-bound (n = 107) or conventionally selected spermatozoa (n = 112) in a randomized way. All of the participants were infertile couples who had normal sperm parameters but low fertilization rate in previous in vitro fertilization (IVF) cycle (n = 5) or experienced multiple IVF failures (n = 13). Lower fertilization (75.7% vs 83.0%) and cleavage rate on day 2 (72.9% vs 83.0%) was observed in oocytes injected with HA-bound spermatozoa than the conventional group, but the difference was not significant. Significantly lower cleavage rate was observed on day 3 in HA group (56.0% vs 69.6%, P = 0.038). Blastocyst formation rate and the number of transferred embryos were similar in both groups. In multiple IVF failure patients, significantly reduced fertilization rate (71.8% vs 85.3%, P = 0.046) and cleavage rate on day 2 (70.4% vs 85.3%, P = 0.029) and day 3 (53.5% vs 77.3%, P = 0.002) were noticed in HA group. Five women achieved pregnancy continuing more than 12 weeks after transfer (27.8%). Success of ICSI was not related with the number of embryos fertilized by HA-bound spermatozoa. Application of ICSI by sperm selection using HA binding is not helpful in couples with repeated poor fertilization or implantation despite normal sperm parameters.

Sperm preparation: state-of-the-art--physiological aspects and application of advanced sperm preparation methods

For assisted reproduction technologies (ART), numerous techniques were developed to isolate spermatozoa capable of fertilizing oocytes. While early methodologies only focused on isolating viable, motile spermatozoa, with progress of ART, particularly intracytoplasmic sperm injection (ICSI), it became clear that these parameters are insufficient for the identification of the most suitable spermatozoon for fertilization. Conventional sperm preparation techniques, namely, swim-up, density gradient centrifugation and glass wool filtration, are not efficient enough to produce sperm populations free of DNA damage, because these techniques are not physiological and not modeled on the stringent sperm selection processes taking place in the female genital tract. These processes only allow one male germ cell out of tens of millions to fuse with the oocyte. Sites of sperm selection in the female genital tract are the cervix, uterus, uterotubal junction, oviduct, cumulus oophorus and the zona pellucida. Newer strategies of sperm preparation are founded on: (i) morphological assessment by means of 'motile sperm organelle morphological examination (MSOME)'; (ii) electrical charge; and (iii) molecular binding characteristics of the sperm cell. Whereas separation methods based on electrical charge take advantage of the sperm's adherence to a test tube surface or separate in an electrophoresis, molecular binding techniques use Annexin V or hyaluronic acid (HA) as substrates. Techniques in this category are magnet-activated cell sorting, Annexin V-activated glass wool filtration, flow cytometry and picked spermatozoa for ICSI (PICSI) from HA-coated dishes and HA-containing media. Future developments may include Raman microspectrometry, confocal light absorption and scattering spectroscopic microscopy and polarization microscopy.

Effects of advanced selection methods on sperm quality and ART outcome: a systematic review

BACKGROUND

Current routine semen preparation techniques do not inclusively target all intrinsic sperm characteristics that may impact the fertilization potential. In order to address these characteristics, several methods have been recently developed and applied to sperm selection. The objective of this study was to systematically review the literature describing these advanced sperm selection methods focusing on their anticipated benefits on sperm quality and assisted reproductive technique (ART) outcome.

METHODS

Systematic literature review was conducted by means of a Medline literature search. Sperm quality parameters assessed included: motility, morphology, viability, DNA integrity, apoptosis and maturity. ART outcomes assessed included: fertilization, embryo quality, pregnancy, abortion and live birth rates.

RESULTS

A total of 44 studies were identified describing four advanced sperm selection methods based on: (i) surface charge (electrophoresis and zeta potential), (ii) apoptosis (magnetic cell sorting and glass wool), (iii) membrane maturity (hyaluronic acid binding) and (iv) ultramorphology (high magnification). Selection of high-quality sperm including improvements in DNA integrity, resulted from the application of these methods. Fertilization and pregnancy rates showed improvement following some of the advanced sperm selection techniques.

CONCLUSIONS

While some of the advanced sperm selection methods are of value in specific clinical ART settings, others are in need of further evaluation. More clinical studies on safety and efficacy are needed before the implementation of advanced sperm selection methods could be universally recommended in ART.

Efficiency of hyaluronic acid (HA) sperm selection

PURPOSE

Hyaluronic Acid (HA) has a role as "physiologic selector" for spermatozoa prior to intracytoplasmic sperm injection (ICSI). The objective of this study is to analyze the results achievable by the introduction of a routine HA-ICSI programme.

METHODS

We retrospectively observed 293 couples treated with HA-ICSI versus 86 couples treated with conventional PVP-ICSI (historical control group). ICSI was performed on a limited number of oocytes per patient (1-3) according to Italian IVF law at the time of the study. Main outcome measures observed were: fertilization, embryo quality, implantation and pregnancy.

RESULTS

This study showed that Injection of HA-bound spermatozoa (HA-ICSI) significantly improves embryo quality and implantation.

CONCLUSIONS

If wider multi-center randomized studies will confirm these beneficial effects on ICSI outcome, HA could be considered as a routine choice for "physiologic" sperm selection prior to ICSI.