Mitochondrial dysfunction and oxidative stress caused by cryopreservation in reproductive cells

Mitochondria, fundamental organelles in cell metabolism, and ATP synthesis are respon-sible for generating reactive oxygen species (ROS), calcium homeostasis, and cell death. Mitochon-dria produce most ROS, and when levels exceed the antioxidant defenses, oxidative stress (OS) is generated. These changes may eventually impair the electron transport chain, resulting in decreased ATP synthesis, increased ROS production, altered mitochondrial membrane permeability, and dis-ruption of calcium homeostasis. Mitochondria play a key role in the gamete competence to facilitate normal embryo development. However, iatrogenic factors in assisted reproductive technologies (ART) may affect their functional competence, leading to an abnormal reproductive outcome. Cry-opreservation, a fundamental technology in ART, may compromise mitochondrial function leading to elevated intracellular OS that decreases sperm and oocytes’ competence and the dynamics of fertilization and embryo development. This article aims to review the role played by mitochondria and ROS in sperm and oocyte function and the close, biunivocal relationships between mitochon-drial damage and ROS generation during cryopreservation of gametes and gonadal tissues in different species. Based on current literature, we propose tentative hypothesis of mechanisms involved in cryopreservation-associated mitochondrial dysfunction in gametes, and discuss the role played by antioxidants and other agents to retain the competence of cryopreserved reproductive cells and tissues

Histogenesis and Histomorphometric study of Human Fetal Small Intestine

Background: Intestine plays a major role for the normal growth of the fetus during the prenatal period. The process of the embryonic development is not quantified histologically. Therefore the main aim of the study was to measure the thickness of all part of the wall of the small intestine that are mucosa, submucosa and muscularis externa and to look for the appearance of the Brunner’s glands and Peyer’s patches in the submucosa of duodenum and ileum.Methods: The present study was carried out on 30 fetuses of gestational ages ranging from 11-36 weeks. Ten fetuses from each trimester were used in the study. Fetal small intestine were dissected carefully, and were separated as duodenum, jejunum & ileum and fixed in formalin solution. The tissue was processed for histology and then slides were stained with Haematoxylin and Eosin. The microscopic features were noted using light microscope.Results: The thickness of the mucosa, submucosa and the muscularis externa was observed to be increased in first trimester, decreased in the second trimester and again increased in the third trimester, which could be because of the increase cell turnover and the arrangement of the collagen fibers as to support the mucosa and the muscularis externa.Conclusion: Thus, the knowledge of the histogenesis and histomorphometry of the human fetal small intestine is crucial for the adult gastroenterologist to appreciate, because of the potential for these early life events to affect the responsiveness of the intestine to physiological or pathological challenges in later life.

Preimplantation diagnosis of genetic diseases

One of the landmarks in clinical genetics is prenatal diagnosis of genetic disorders. The recent advances in the field have made it possible to diagnose the genetic conditions in the embryos before implantation in a setting of in vitro fertilization. Polymerase chain reaction and fluorescence in situ hybridization are the two common techniques employed on a single or two cells obtained via embryo biopsy. The couple who seek in vitro fertilization may screen their embryos for aneuploidy and the couple at risk for a monogenic disorder but averse to abortion of the affected fetuses after prenatal diagnosis, are likely to be the best candidates to undergo this procedure. This article reviews the technique, indications, benefits, and limitations of pre-implantation genetic testing in clinical practice

Preimplantation diagnosis of genetic diseases

One of the landmarks in clinical genetics is prenatal diagnosis of genetic disorders. The recent advances in the field have made it possible to diagnose the genetic conditions in the embryos before implantation in a setting of in vitro fertilization. Polymerase chain reaction and fluorescence in situ hybridization are the two common techniques employed on a single or two cells obtained via embryo biopsy. The couple who seek in vitro fertilization may screen their embryos for aneuploidy and the couple at risk for a monogenic disorder but averse to abortion of the affected fetuses after prenatal diagnosis, are likely to be the best candidates to undergo this procedure. This article reviews the technique, indications, benefits, and limitations of pre-implantation genetic testing in clinical practice

Effect of Vitamin D Analogue on Rosuvastatin-Induced Myopathy in Wistar Rats

Objectives. Statin-induced myopathy is one of the major causes of poor adherence and discontinuation of this medication. There are contrary results regarding association of vitamin D insufficiency with statin-induced myopathy. This study was done to determine the effect of the vitamin D3 analogue alfacalcidol on Rosuvastatin-induced myopathy in rats. Methodology. Animals were divided into six groups with 6 rats in each group. Groups I and II acted as controls, Group III and Group IV were administered Rosuvastatin 120 mg/kg/day and 160 mg/kg/day, Groups V and VI were administered alfacalcidol 0.1 μg/kg/day in addition to Rosuvastatin 120 mg/kg/day and 160 mg/kg/day, respectively. All drugs were administered orally for 15 days. Plasma creatine kinase (CK) levels were estimated on day 10 and day 15. Animals were sacrificed and muscles were sent for histopathological examination. Results. On day 10, Groups V and VI showed a statistically significant increase in plasma CK levels as compared to the control (p0.05). On comparing the histology, Groups V and VI showed a significant difference as compared to statin-only groups (Groups III and IV) as there were signs of regeneration, less splitting, and fragmentation of muscle fibres. Conclusion. The present study shows that the vitamin D analogue alfacalcidol prevents statin-induced myopathy. The serum CK levels are comparable to the control group on day 15 of vitamin D administration

Germinal stage vitrification is superior to MII stage vitrification in prepubertal mouse oocytes

This study investigated if in vitro maturation (IVM) before or after vitrification would be more successful for prepubertal oocytes. To mimic prepubertal conditions in an experimental setup, oocytes were collected from healthy 14, 21 and 28day old Swiss albino mice. The germinal vesicle (GV) stage oocytes and in vitro matured MII oocytes were subjected to vitrification-warming. Both structural (meiotic spindle morphology, mitochondrial integrity, cortical granules) and functional (sperm zona binding, fertilization) characteristics were assessed in oocytes after warming. This study demonstrated that IVM was more detrimental to prepubertal oocytes than to young adults. Further, vitrification of the IVM oocytes resulted in an increase in the number of abnormal meiotic spindles, a change in the cortical distribution pattern, a reduction in sperm zona binding and the fertilization rate. Importantly, oocyte integrity was better when prepubertal oocytes were vitrified before, rather than after, IVM. The above observations support GV stage vitrification for prepubertal oocytes requiring fertility preservation. Understanding the mechanisms behind the differing outcomes for oocytes from immature females will help in refining current protocol, thereby retaining the oocytes' maximum structural and functional integrity Further investigation is necessary to determine whether human prepubertal oocytes also behave in a similar way. It is to be noted here, with great emphasis, that a major limitation of this study is that the oocytes’ abilities were tested only until fertilisation, as a consequence of which the study cannot reveal the developmental potentials of the embryos beyond fertilisation

Thyroid anomalies with its embryological and clinical correlation

Objective: Thyroid gland is the first endocrine gland to start developing in the embryo. It is well-known for its developmental anomalies such as persistence of pyramidal lobe, thyroglossal duct, agenesis of isthmus, agenesis or hemiagenesis of thyroid gland, or aberrant thyroid glands. These anomalies may cause clinical functional disorders and should be kept in mind while doing surgery on the gland. Materials and Methods: A study was conducted on 37 cadavers to look for the anomalies of thyroid gland. Results: We observed six cases of agenesis of the isthmus of the thyroid gland. Four cases were of agenesis of isthmus alone, fifth case had isthmus agenesis with duplication of the thyroglossal duct remnant and a pyramidal lobe, and sixth one had isthmus agenesis with a thyroglossal duct which divides before entering the two lateral lobes. Conclusion: Such knowledge is very essential for the surgeon while performing thyroid surgeries. Understanding the surgical anatomy of the thyroid gland and its possible variations is essential for safe and effective surgery

Reduced ovarian response to controlled ovarian stimulation is associated with increased oxidative stress in the follicular environment

Serum estradiol (E2) level is routinely used to monitor the ovarian response during controlled ovarian hyperstimulation (COH) and the concentration of serum E2 may influence the oocyte quality and pregnancy outcome. However, the knowledge on the association between COH induced serum E2 level, oocyte quality and embryo development is limited. Therefore we investigated the association between serum E2 level, oxidative stress in the follicular fluid and granulosa cells (GCs) response to elucidate the association between E2 level and embryological outcome. In this study, patients (n = 30) undergoing ART were categorized as ‘normal responders’ (NR, n = 10), ‘poor responders’ (PR, n = 10) and hyper responders (HR, n = 10). The follicular fluid malondialdehyde (MDA) level was determined. The total RNA extracted from GCs was subjected to analyse the relative abundance of transcripts of stress response genes (P53, caspase 3,8-oxoguanine DNA glycosylase, OGG1 and heat shock protein 70; HSP70) and embryological outcome was noted. Follicular fluid MDA level was significantly higher in PR (p < 0.01) compared NR and HR whereas number of top-quality embryos were significantly lower in PR and HR compared to NR (p < 0.01). The relative expression of P53, HSP70, and OGG1 in GCs was significantly elevated in PR (p < 0.05−0.01). An inverse relationship was established between serum E2 level vs follicular MDA level (r = −0.45; p < 0.01) and follicular MDA level vs. number of top-quality embryos (r = −0.45; p < 0.01). Hence, patients with low serum E2 had elevated oxidative stress in their follicular environment and poor quality embryos implicating the risk of oxidative stress in patients with poor ovarian response