Cryopreservation of human genetic material

Fluorescent enzyme-based biosensor for sensitive analysis of DNA damage in cryopreserved sperm

The freeze-thaw process can induce irreversible structural and functional changes in human sperm, particularly sperm DNA damage. Selecting a more accurate and sensitive detection method for evaluating sperm DNA integrity is crucial. To accurately assess sperm DNA integrity following the freeze-thaw process and significantly improve the clinical and scientific utilization of cryopreserved sperm. In this study, we utilized a novel fluorescent biosensor, assisted by terminal deoxynucleotidyl transferase (TdT) and Endonuclease IV, to detect DNA breakpoints during sperm cryopreservation. We evaluated the biosensor's performance by comparing it with the conventional DNA fragmentation index (DFI) measured using sperm chromatin structure analysis (SCSA). The cryopreserved group exhibited a significantly higher sperm DFI compared to the fresh group. No significant difference was observed between the antioxidant group and the cryopreserved group. However, the new method revealed a significant reduction in the number of DNA breakpoints in the antioxidant group compared to the cryopreserved group. The novel biosensor demonstrated superior accuracy and effectiveness in assessing sperm DNA integrity during cryopreservation compared to the conventional SCSA method. We believe that the biosensor holds significant potential for widespread use in the field of reproductive medicine.

Human sperm parameter improvement associated with Ceratonia siliqua extract as a cryopreservation supplement after vitrification

OBJECTIVE

Given the destructive effects of oxidative stress on sperm structure, this study was conducted to investigate the antioxidant effects of different concentrations of Ceratonia siliqua plant extract on human sperm parameters after the freezing-thawing process.

METHODS

A total of 20 normozoospermic samples were frozen. Each sample was divided into two control groups (fresh and cryopreservation) and three cryopreservation experimental groups (containing C. siliqua extract at concentrations of 20, 30, and 40 μg/mL in the freezing extender). Motility, intracellular levels of reactive oxygen species (ROS), plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), viability, and acrosome reaction parameters were evaluated.

RESULTS

Statistical analysis showed that the highest motility, viability, and PMI were associated with the 20 μg/mL concentration of C. siliqua extract. At all concentrations, intracellular ROS levels were significantly lower and the levels of MMP and the acrosome reaction were significantly higher than in the cryopreservation control group (p≤0.05).

CONCLUSION

C. siliqua extract supplements at concentrations of 20, 30, and 40 μg/mL improved sperm motility, viability, PMI, MMP, intracellular ROS, and the acrosome reaction.

Knockout serum replacement is an efficient serum substitute for cryopreservation of human spermatozoa

The freeze-thaw procedure causes irreversible structural and functional changes in human spermatozoa. In order to decrease the detrimental effects of cryopreservation and improve the quality of post-thawed spermatozoa, the constituents of the freezing solution attracted considerable attention. In this study, for the first time, we evaluated the efficacy of knockout serum replacement (KSR) as a substitute for human serum albumin (HSA) for cryopreservation of human spermatozoa. Twenty semen samples were collected from normozoospermic men and divided them into five equal groups. One of the aliquots was diluted with glycerol-based medium as a control group (CON). The other four aliquots were diluted with the sucrose solution containing 5% HSA (H5), 10% HSA (H10), 5% KSR (K5), and 10% KSR (K10). The diluted samples were frozen and preserved in liquid nitrogen. Post thawed sperm parameters including motion characteristics, viability, membrane integrity, mitochondrial activity, acrosome integrity and DNA intactness in all of the sucrose-based groups were comparable with glycerol-based medium. The replacement of HSA by 10% KSR in the freezing medium resulted in significantly higher post-thawed viability, acrosome integrity and DNA intactness compared with other sucrose-based groups. In conclusion, the addition of 10% KSR to the sucrose-based freezing solution improves the quality of post-thawed human spermatozoa and may have potential to develop chemically defined freezing medium.

Quebec public funding facilitates fertility preservation for male cancer patients

BACKGROUND

Sperm cryopreservation remains the only clinically feasible option to preserve male fertility. The quality of counselling provided by the treating physicians and the cost of sperm cryopreservation can both influence a patient's decision about whether to preserve sperm. On 5 August 2010, the Quebec government introduced provincial coverage of assisted reproductive technologies, with sperm cryopreservation included as a covered service. The aim of the present study was to evaluate whether and how such a program affects the behaviour of cancer patients with respect to sperm cryopreservation.

METHODS

We analyzed the database derived from male patients undergoing sperm cryopreservation from August 2008 to August 2012 at our centre. The retrieved data included patient age, male infertility or oncologic diagnosis, sperm quality parameters, and details about the number of visits for sperm cryopreservation.

RESULTS

The number of cancer patients who cryopreserved sperm before and after the policy change did not differ significantly, but a marked increase in the number of non-cancer patients was observed. Further analysis revealed that, after implementation of the public funding program, the total number of sperm cryopreservation sessions per patient increased significantly in cancer patients but not in non-cancer patients.

CONCLUSIONS

It appears that cancer patients who are willing to freeze sperm are keen to return for more sessions of sperm banking when no fees are associated with the service. Those findings suggest that cost reduction is an important factor for improving delivery of fertility preservation services to male cancer patients.

Assisted reproductive outcomes of male cancer survivors

PURPOSE

The objective of our study was to evaluate the reproductive outcome of male cancer survivors treated with intracytoplasmic sperm injection (ICSI) using cryopreserved sperm and compare it with the same treatment in non-cancer males.

METHODS

We retrospectively analyzed database derived from cancer and non-cancer patients undergoing sperm cryopreservation from August 2008 to August 2012 at a university-based center. We evaluated the reproductive outcome of those cancer and non-cancer patients that had frozen sperm and returned subsequently to the clinic for assisted reproduction.

RESULTS

We studied 272 males with cancer and 296 infertile males. The most prevalent types of cancer in our cohort were lymphoma (25.3 %), testicular cancer (19.2 %), leukemia (7.3 %), and other malignancies including sarcoma, gastrointestinal, and central nervous system malignancies (48.2 %). The use rate of cryopreserved sperm was 10.7 % for cancer patients and 30.7 % for non-cancer patients. The mean age of males with cancer who returned to the clinic for fertility treatment was 36.7 ± 6 years, and the diagnoses were testis cancer (43.4 %), lymphoma (36.9 %), leukemia (13 %), and other malignancies (6.7 %). Live birth rate of the cancer cohort was 62.1 %, which was higher than that of the normospermic non-cancer population (p < 0.0047).

CONCLUSIONS

The use rate of cryopreserved sperm from oncofertility preservation cases is at around 10 %. The live birth rate using assisted reproductive technologies among these patients is at least comparable to that of the non-cancer population.

IMPLICATIONS FOR CANCER SURVIVORS

To our knowledge, this was the first comparative study of male cancer survivors treated with ICSI using cryopreserved sperm, which were compared to non-cancer males undergoing the same treatment. Male fertility preservation is a highly valued service that should be strongly encouraged prior to beginning cytotoxic cancer treatment. These results can help healthcare professionals in oncology to improve the quality of counseling on fertility preservation when managing young men with newly diagnosed cancer that require gonadotoxic treatment.

Density gradient centrifugation prior to cryopreservation and hypotaurine supplementation improve post-thaw quality of sperm from infertile men with oligoasthenoteratozoospermia

STUDY QUESTION

Can selection of spermatozoa by density gradient centrifugation prior to cryopreservation and/or hypotaurine supplementation improve the post-thaw quality of sperm from infertile men with oligoasthenoteratozoospermia?

SUMMARY ANSWER

Sperm selection by density gradient centrifugation before freezing and supplementation of the media by hypotaurine is beneficial for the cryopreservation of semen samples of patients with oligoasthenoteratozoospermia.

WHAT IS KNOWN ALREADY

Sperm from men with oligoasthenoteratozoospermia are more susceptible than normal to cryoinjury. Density gradient centrifugation before sperm freezing may allow the selection of a subpopulation of spermatozoa more resistant to cryopreservation. Hypotaurine is an antioxidant with a protective effect on sperm functions.

STUDY DESIGN, SIZE, DURATION

The experiment was carried out according to a factorial design involving two binary factors resulting in four treatment combinations which were randomly allocated in oligoasthenoteratozoospermia sperm samples from 64 patients recruited between January 2009 and June 2010.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Semen was provided by 64 men undergoing evaluation for infertility at the Centre for Reproductive Medicine of the University Hospital in Clermont-Ferrand, France, between January 2009 and June 2010. Four treatment combinations were tested: sperm freezing before selection without (F-S/H-; n = 16) and with hypotaurine supplementation (F-S/H+; n = 16); sperm selection before freezing without (S-F/H-; n = 16) and with hypotaurine supplementation (S-F/H+; n = 16). Measurements of sperm recovery rates and markers of apoptosis (externalization of phosphatidylserine (PS), mitochondrial membrane potential and DNA fragmentation) were compared in recovered spermatozoa after each procedure.

MAIN RESULTS AND THE ROLE OF CHANCE

Higher recovery rates of progressive and total motile spermatozoa were observed when sperm selection was performed before freezing (P < 0.05). The protective effect of hypotaurine was only observed on the percentage of live spermatozoa with PS externalization among total live spermatozoa (AN+ PI-/((AN+ PI-) + (AN- PI-)) when the sperm selection by density gradient centrifugation was performed before freezing (S-F/H+ versus S-F/H-: 6.8 ± 1.09 versus 11.8 ± 2.03%, P = 0.04). The percentage of mitochondrial membrane potential (DiOC6(3) (high)) spermatozoa was higher (P = 0.001) when sperm selection was done before freezing compared with procedures in which sperm selection was done after sperm freezing with (S-F/H+ versus F-S/H+: 58.1 ± 3.50 versus 46.7 ± 5.48%) or without (S-F/H- versus F-S/H-: 57.0 ± 5.18 versus 35.4 ± 4.99%) hypotaurine supplementation. The percentages of TUNEL+ spermatozoa were significantly lower (P = 0.001) when sperm selection was done before sperm freezing compared with procedures in which sperm selection was done after sperm freezing with (S-F/H+ versus F-S/H+: 38.6 ± 9.59 versus 55.7 ± 5.88%) or without hypotaurine supplementation (S-F/H- versus F-S/H-: 37.2 ± 7.91 versus 71.0 ± 5.66%).

LIMITATIONS, REASONS FOR CAUTION

The ICSI outcomes were not assessed and the fertility of the spermatozoa remains unknown.

WIDER IMPLICATIONS OF THE FINDINGS

Sperm selection by density gradient centrifugation before freezing and hypotaurine supplementation could improve the cryopreservation of sperm from oligoasthenoteratozoospermic men and make a larger number of functional spermatozoa available for ICSI.

STUDY FUNDING/COMPETING INTERETS(S)

This work was supported by a hospital grant (Projet Hospitalier Recherche Clinique, CHU Clermont Ferrand, France). None of the authors has any conflict of interest to declare.

Pregnancies beyond the Human Biological Fecundity

The maternal age at first delivery constantly rises in developed countries due to a social trend to postpone the age of parenting. Assisted reproduction technologies do extend the age of fecundity to some limit, but their success rate is inversely related to the patients' age. The major factor limiting human fecundity in the fifth decade of life is the quality of the human oocyte. This problem can be readily bypassed using oocytes from young donors thus significantly extending the age limit in which conception and delivery are possible well into menopause. The ability to become pregnant and deliver at such an age raises serious medical, moral, social and legal concerns regarding the health and welfare of the mother, child and oocyte donor, which will be presented and discussed here.

Three-dimensional culture of mouse bone marrow cells on stroma formed within a porous scaffold: influence of scaffold shape and cryopreservation of the stromal layer on expansion of haematopoietic progenitor cells

This study's primary goal was to develop an effective ex vivo expansion method for haematopoietic cells. 3D culture of mouse bone marrow cells was performed in porous scaffolds using a sheet or cube shape. Bone marrow cells were cultured on bone marrow-derived stromal layers formed within the scaffolds and the effect of scaffold shape on the expansion of haematopoietic cells was examined. In some experiments, stromal layers within cubic scaffolds were frozen and then used to culture bone marrow cells after thawing. Results show that after comparison, total cell density and expansion of haematopoietic cells were greater in cultures using the cubic scaffold, suggesting that it was superior to the sheet-like scaffold for expanding haematopoietic cells. When cryopreserved stroma was used, it effectively supported the expansion of haematopoietic cells, and a greater expansion of haematopoietic cells [(erythroid and haematopoietic progenitor cells (HPCs)] was achieved than in cultures with stromal cells that had not been cryopreserved. Expansion of cells using cryopreserved stroma had several other advantages such as a shorter culture period than the conventional method, a stable supply of stromal cells, and ease of handling and scaling up. As a result, this is an attractive method for ex vivo expansion of haematopoietic stem cells (HSCs) and HPCs for clinical use.