Ethical issues in human reproduction: Catholic perspectives

Abstract

The catholic perspective in human reproduction is based on the concept that the human being is to be respected and treated as a person from the moment of conception. In this paper the ethical implications derived from such a principle are discussed.     

Leukemia inhibitory factor in human reproduction

Objective: To describe the clinical findings, expressions, interactions, and clinical implications of leukemia inhibitory factor (LIF) in human reproduction.

Design: Review of published articles.

Setting: Clinical development unit of biotechnology company.

Intervention(s): None.

Result(s): In the endometrium, LIF is expressed in a menstrual cycle–dependent manner, with the highest level occurring at the time of implantation. LIF is also detected in uterine flushing, and its level is significantly lower in women with unexplained infertility. Likewise, endometrial explants derived from women with unexplained infertility showed reduced levels of LIF secretion. Binding of LIF to LIF receptor and gp130 activates signal transduction pathways. LIF receptor is expressed in endometrium, oocytes, and blastocysts. Cytotrophoblasts cultured in the presence of LIF differentiate toward an anchoring extravillous phenotype.

Conclusion(s): On the basis of reports gathered from animal and human studies, LIF appears to play an important role in implantation and in the establishment of pregnancy.     

Melatonin and human reproduction: Shedding light on the darkness hormone

Melatonin, N-acetyl-5-methoxytryptamine, is a molecule with diverse physiological functions. This neuro-hormone affects reproductive performance in a wide variety of species. In most animals, but not exclusively all, melatonin has an antigonadotrophic effect. The seasonal changes in the number of hours per day that melatonin is secreted mediate the temporal coupling of reproductive activity to seasonal changes in day-length. These observations stimulated a search for a role for the pineal gland and melatonin in human reproduction. Clinical experience related to this issue has yielded inconclusive and sometimes conflicting results. This article reviews the current available evidence concerning the effects of melatonin on human reproductive processes (e.g., puberty, ovulation, pregnancy, and fertility). Possible reasons for the vagueness and elusiveness of the clinical effects are discussed.     

Leptin and reproduction: a review

OBJECTIVE: To review recent advances in understanding the role of leptin in the physiology and pathophysiology of reproduction, with a focus on relevant clinical situations. DESIGN: A MEDLINE computer search was performed to identify relevant articles. RESULT(S): Leptin, an adipocyte hormone important in regulating energy homeostasis, interacts with the reproductive axis at multiple sites, with stimulatory effects at the hypothalamus and pituitary and inhibitory actions at the gonads. More recently, leptin has been shown to play a role in other target reproductive organs, such as the endometrium, placenta, and mammary gland, with corresponding influences on important physiologic processes such as menstruation, pregnancy, and lactation. As a marker of whether nutritional stores are adequate, leptin may act in concert with gonadotropins and the growth hormone axis to initiate the complex process of puberty. Conditions in which nutritional status is suboptimal, such as eating disorders, exercise-induced amenorrhea, and functional hypothalamic amenorrhea, are associated with low serum leptin levels; and conditions with excess energy stores or metabolic disturbances, such as obesity and polycystic ovarian syndrome, often have elevated serum or follicular fluid leptin levels, raising the possibility that relative leptin deficiency or resistance may be at least partly responsible for the reproductive abnormalities that occur with these conditions. CONCLUSION(S): Leptin may act as the critical link between adipose tissue and the reproductive system, indicating whether adequate energy reserves are present for normal reproductive function. Future interventional studies involving leptin administration are expected to further clarify this role of leptin and may provide new therapeutic options for the reproductive dysfunction associated with states of relative leptin deficiency or resistance.     

Progress in understanding human ovarian folliculogenesis and its implications in assisted reproduction

Purpose

To highlight recent progress in understanding the pattern of follicular wave emergence of human menstrual cycle, providing a brief overview of the new options for human ovarian stimulation and oocyte retrieval by making full use of follicular physiological waves of the patients either with normal or abnormal ovarian reserve.

Methods

Literature review and editorial commentary.

Results

There has been increasing evidence to suggest that multiple (two or three) antral follicular waves are recruited during human menstrual cycle. The treatment regimens designed based on the theory of follicular waves, to promote increased success with assisted reproduction technology (ART) and fertility preservation have been reported. These new options for human ovarian stimulation and oocyte retrieval by making full use of follicular waves of the patients either with normal or abnormal ovarian reserve lead to new thinking about the standard protocols in ART and challenge the traditional theory that a single wave of antral follicles grows only during the follicular phase of the menstrual cycle.

Conclusions

The understanding of human ovarian folliculogenesis may have profound implications in ART and fertility preservation. Further studies are needed to evaluate the optimal regimens in ART based on the theory of follicular waves and to identify non-invasive markers for predicting the outcome and the potential utilities of follicles obtained from anovulatory follicular waves in ART.     

维生素D与男性生殖关系的研究进展

维生素D为人们所熟知的,其生理功能是参与钙磷代谢与骨盐沉积.近年来研究表明,维生素D受体在男性生殖器官中广泛表达,相关研究还证实了维生素D缺乏或不足与男性生育力下降存在相关性.本文主要从维生素D生物和代谢特点及其在男性生殖各方面的作用进行综述,以便加深对维生素D在男性生殖中作用的认识,为男性不育的治疗提供理论依据.     

Homocysteine and human reproduction

Homocysteine is an amino acid that is capable of disturbing the proper growth of cells. Hyperhomocysteinemia can lead to a non-closure of the neural tube. The underlying basis is a derangement of homocysteine metabolism due to a missense mutation of the MTHFR enzyme that has to catalyze the folate metabolic cycle furnishing sufficient methyl groups for DNA and tRNA synthesis. Folate can overcome the dysfunction of the mutation and the decreased activity of the thermolabile MTHFR. Homocysteine is also recognized as an independent risk factor for obstetrical vascular disease that can manifest itself in maternal veins (thrombosis), arteries (preeclampsia) or spiral arteries supplying the placenta (placental abruption). Low vitamin status (folic acid, vitamin B6 and B12), hyperhomocysteinemia, the MTHFR gene mutation C677T, and thrombotic factors like Protein C, Protein S. antithrombin III, factor V Leiden and Activated Protein C, are alone or in combination high risk factors for obstetrical vascular disease. Their values can be modulated by B-vitamin status and could be able to prevent disease from occurring or recurring. Placebo-randomized trials have been done in neural tube defects but are urgently needed in the vascular area. The common denominator of the effect of homocysteine on the embryo and the blood vessels (endothelium) could be sited in the process of proliferation of cells that need proper methyl groups for proper function.     

Role of religion,spirituality, and faith in assisted reproduction

Purpose: The purpose of this study is to evaluate the impact of the patient’s faith, religion, and spirituality on the outcomes of intracytoplasmic sperm injection (ICSI) cycles.

Materials and methods: Eight hundred and seventy-seven patients received a questionnaire containing information on faith, religiosity, and spirituality and the results of the questionnaires were correlated with ICSI outcomes. Patients stated to be Catholic (n?=?476), spiritists (n?=?93), Evangelical (n?=?118), and other religion (n?=?32), and 78 did not identify with any religious group.

Results: A significant increase in fertilization, high-quality embryos, and pregnancy rate was found among Spiritists and Evangelicals. Patients who included the infertility diagnosis and treatment in their prayers showed an increased pregnancy rate, and those who reported their faith to be affected by the infertility diagnosis presented a decreased high-quality embryos rate. The high-quality embryos rate was increased among patients who answered that their faith contributed to their decision to undergo infertility treatment. The cycle’s cancelation was negatively correlated with the frequency of religious meetings, and the frequency of prayers was positively correlated with the response to ovarian stimulation. Finally, belief in treatment success positively influenced the embryo quality.

Conclusion: The findings suggest that spirituality plays a role in adjusting the psychological aspects of an infertile patient.     

The role of autophagy in reproduction from gametogenesis to parturition

Autophagy is an intracellular process responsible for maintaining cellular homeostasis by the removal of cytoplasmic organelles, intracellular bacteria and viruses, and is a critical component of both the innate and acquired immune systems. A failure in physiological activation, assembly and function of the autophagic pathway has been implicated in a broad range of diseases including neurogenerative diseases, cardiopathy, infectious diseases, autoimmunity and cancer. Its involvement in reproduction, however, has not been extensively studied. Its activity is fundamental to many processes across the reproduction spectrum from development of the primordial follicle and spermatozoa to embryogenesis, placental development and maintaining uterine quiescence during pregnancy. Malfunctions in autophagy are associated with deleterious repercussions throughout reproduction. In this review we examine what is known about the involvement of autophagy in gamete formation, early post-fertilization embryogenesis, placental development and parturition, and propose promising areas for future research.