P A Milne

Bio: P A Milne is an academic researcher. The author has contributed to research in topics: DNA damage & DNA fragmentation. The author has an hindex of 2, co-authored 2 publications receiving 1398 citations.

Relative Impact of Oxidative Stress on the Functional Competence and Genomic Integrity of Human Spermatozoa

Abstract: Reactive oxygen metabolites are known to disrupt sperm-oocyte fusion, sperm movement, and DNA integrity; however, the relative sensitivities of these elements to oxidative stress are unknown. In this study these factors were assessed in human spermatozoa exposed to increasing levels of oxidative stress achieved through the stimulation of endogenous oxidant generation with NADPH or direct exposure to hydrogen peroxide. At low levels of oxidative stress, DNA fragmentation was significantly reduced while the rates of sperm-oocyte fusion were significantly enhanced. As the level of oxidative stress increased, the spermatozoa exhibited significantly elevated levels of DNA damage (p < 0.001) and yet continued to express an enhanced capacity for sperm-oocyte fusion. At the highest levels of oxidative stress, extremely high rates of DNA fragmentation were observed but the spermatozoa exhibited a parallel loss in their capacities for movement and oocyte fusion. These studies emphasize how redox mechanisms can either enhance or disrupt the functional and genomic integrity of human spermatozoa depending on the intensity of the oxidative stimulus. Because these qualities are affected at different rates, spermatozoa exhibiting significant DNA damage are still capable of fertilizing the oocyte. These results may have long-term implications for the safety of assisted conception procedures in cases associated with oxidative stress.

DNA Integrity in Human Spermatozoa: Relationships With Semen Quality

Abstract: The literature contains conflicting evidence regarding the existence of DNA damage in spermatozoa from infertile male patients. To examine this phenomenon, we have studied ejaculated spermatozoa from normozoospermic semen donors and from a group of the unselected male partners of couples attending an infertility clinic for initial investigation. Classical semen analysis according to World Health Organization (WHO) guidelines was undertaken with computer-assisted sperm analysis (CASA). Spermatozoa were prepared by sequential washing and centrifugation and were analyzed for DNA fragmentation using three assays: 1) a single-cell gel electrophoresis (comet) assay, 2) in situ nick translation with prior chemical decondensation (ISNT-decondensed), and 3) in situ nick translation without prior chemical decondensation (ISNT-condensed). In addition, reactive oxygen species (ROS) generation by spermatozoa was measured, and seminal plasma was analyzed for its total reactive antioxidant potential (TRAP). When the donor and patient groups were compared, the latter had lower levels of semen quality and higher levels of DNA damage, which was particularly apparent using the comet assay. Highly significant negative correlations were observed between DNA fragmentation, detected by all three assays, and semen quality, particularly sperm concentration. In addition, multiple regression analysis indicated that other attributes of semen quality, such as sperm movement and ROS generation, were also related to DNA damage. We conclude that a significant proportion of infertile men have elevated levels of DNA damage in their ejaculated spermatozoa.

P-482 Male Fertility preservation and pregnancy outcomes in patients facing gonadotoxic therapies

Abstract: Emergency Fertility preservation in male patients- utilisation rate of the stored sperms and pregnancy outcomes 99% of men were able to cryopreserve their sperm before gonadotoxic therapy.9% of the sample were used and of them 62% had successful live birth. The testis is highly susceptible to the toxic effects of radiation and chemotherapy at all stages of life. Cytotoxic chemotherapy and radiotherapy may produce long-lasting or persistent damage to primordial sperm cells, leading to oligo- or azoospermia. Clinicians should inform patients receiving potentially gonadotoxic therapies about options for fertility preservation and future reproduction prior to the initiation of such treatment. The most common strategy to preserve fertility is cryopreservation of sperm before treatment for later use. Cryopreservation of testicular tissue from prepubescent males remains experimental. A retrospective analysis was performed in 367 patients who underwent emergency fertility preservation in our tertiary centre, during a period of 30 years between January 1991 to December 2021. An Infertility database for embryology and andrology s (IDEAS) was used for the data collection and analysis. Patient’s age, reasons for fertility preservation, type of cancer and benign conditions, sperm characteristics, whether the samples were utilized for fertility treatment and any treatment outcomes were included in the analysis. The median age for the men who presented for fertility preservation is 30 years (Range 15- 55). The median number of straws is 9 (Range 1– 18). The referral was made from oncology (33%), haematology (28%) Urology (19%) and other departments (20%). The majority had a diagnosis was testicular cancer (50%), lymphoma (20%), leukaemia (5%) and other causes (25%). A total of 99 % of men had sperms frozen from the ejaculated semen and 1% underwent surgical sperm retrieval for cryopreservation. More than half the population of men at the time of cryopreservation were normospermic in 59%, the rest had oligo/asthenospermia in 40 % and azoospermia in 1 %. Cryopreservation was not possible in 1 % of the patients as they were unable to produce a sample. Nine percent of the sample were used for treatment and of them 62 % resulted in successful Livebirths. Intracytoplasmic sperm injection was the main treatment of choice. The mean Straws were perished electively in 2% and following death in 0.5 % of the study population. Concerns about the welfare of resulting offspring, whether due to an expected shortened lifespan of the parent or effects of cancer or infertility treatment (in the present state of knowledge) ordinarily are not a sufficient reason to deny cancer patients assistance in reproducing. The rate of use of cryopreserved sperm in cancer patients is low.Cancer patients were more likely than non-cancer patients to use or continue storage of banked samples. Sperm banks should be aware of the low rates of straw use and destruction by patients. not applicable

Oxidative stress and male infertility—a clinical perspective

Abstract: Oxidative stress occurs when the production of potentially destructive reactive oxygen species (ROS) exceeds the bodies own natural antioxidant defenses, resulting in cellular damage. Oxidative stress is a common pathology seen in approximately half of all infertile men. ROS, defined as including oxygen ions, free radicals and peroxides are generated by sperm and seminal leukocytes within semen and produce infertility by two key mechanisms. First, they damage the sperm membrane, decreasing sperm motility and its ability to fuse with the oocyte. Second, ROS can alter the sperm DNA, resulting in the passage of defective paternal DNA on to the conceptus. This review will provide an overview of oxidative biochemistry related to sperm health and will identify which men are most at risk of oxidative infertility. Finally, the review will outline methods available for diagnosing oxidative stress and the various treatments available.

Nanomaterials for theranostics: recent advances and future challenges.

Abstract: Challenges Eun-Kyung Lim,†,‡,§ Taekhoon Kim, Soonmyung Paik, Seungjoo Haam, Yong-Min Huh,*,† and Kwangyeol Lee* Department of Chemistry, Korea University, Seoul 136-701, Korea †Department of Radiology, Yonsei University, Seoul 120-752, Korea Severance Biomedical Research Institute, Yonsei University College of Medicine, Seoul 120-749, Korea Division of Pathology, NSABP Foundation, Pittsburgh, Pennsylvania 15212, United States Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 120-749, Korea ‡BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea Electronic Materials Laboratory, Samsung Advanced Institute of Technology, Mt. 14-1, Nongseo-Ri, Giheung-Eup, Yongin-Si, Gyeonggi-Do 449-712, Korea

Role of sperm chromatin abnormalities and DNA damage in male infertility

Abstract: Sperm DNA integrity is essential for the accurate transmission of genetic information. It has a highly compact and complex structure and is capable of decondensation-features that must be present in order for a spermatozoon to be considered fertile. Any form of sperm chromatin abnormalities or DNA damage may result in male infertility. In support of this conclusion, it was reported that in-vivo fecundity decreases progressively when > 30% of the spermatozoa are identified as having DNA damage. Several methods are used to assess sperm chromatin/DNA, which is considered an independent measure of sperm quality that may yield better diagnostic and prognostic approaches than standard sperm parameters (concentration, motility and morphology). The clinical significance of this assessment lies in its association not only with natural conception rates, but also with assisted reproduction success rates. Also, it has a serious impact on the offspring and is highly prognostic in the assessment of fertility in cancer patients. Therefore, screening for sperm DNA damage may provide useful information in cases of male idiopathic infertility and in those men pursuing assisted reproduction. Treatment should include methods for prevention of sperm DNA damage.

Protamines and male infertility.

Abstract: Protamines are the major nuclear sperm proteins. The human sperm nucleus contains two types of protamine: protamine 1 (P1) encoded by a single-copy gene and the family of protamine 2 (P2) proteins (P2, P3 and P4), all also encoded by a single gene that is transcribed and translated into a precursor protein. The protamines were discovered more than a century ago, but their function is not yet fully understood. In fact, different hypotheses have been proposed: condensation of the sperm nucleus into a compact hydrodynamic shape, protection of the genetic message delivered by the spermatozoa, involvement in the processes maintaining the integrity and repair of DNA during or after the nucleohistone-nucleoprotamine transition and involvement in the epigenetic imprinting of the spermatozoa. Protamines are also one of the most variable proteins found in nature, with data supporting a positive Darwinian selection. Changes in the expression of P1 and P2 protamines have been found to be associated with infertility in man. Mutations in the protamine genes have also been found in some infertile patients. Transgenic mice defective in the expression of protamines also present several structural defects in the sperm nucleus and have variable degrees of infertility. There is also evidence that altered levels of protamines may result in an increased susceptibility to injury in the spermatozoan DNA causing infertility or poor outcomes in assisted reproduction. The present work reviews the articles published to date on the relationship between protamines and infertility.