Maddalena Mutinati

Oxidative Stress During Pregnancy In The Sheep

During physiological pregnancy, all tissues and, mostly, placenta and foetus require high amounts of oxygen. Reactive oxygen species (ROS), generated both by mother and foetus, are implicated in foetal growth because they promote replication, differentiation and maturation of cells and organs. Nevertheless, ROS excess, if not properly counterbalanced, may lead to an alteration in cell constituents, with harmful effects both on mother and foetus.ROS exert a biphasic effect because adequate ROS concentration is essential for embryo development, implant, foetal defence against uterine infections, steroidogenesis, pregnancy maintainance and partum. On the other hand, an uncontrolled ROS generation, beyond physiological antioxidant defences, may lead to embryo resorption, placental degeneration with subsequent alteration in maternal-foetal exchanges, delay in foetal growth, pregnancy interruption, stillbirths. This review investigates the mechanisms underlying ROS generation and effects, throughout physiological and pathological pregnancy in sheep, with a look to antioxidants and their importance in such a critical phase of the reproductive cycle of the sheep.

Reactive Oxygen Species (ROS): involvement in bovine follicular cysts etiopathogenesis

Ovulation is compared to an acute inflammatory process during which vasoactive agents, prostanoids, leukotrienes and Reactive Oxygen Species (ROS) develop. The aim of this study was to evaluate the levels of ROS in cystic and follicular fluid, in order to establish their involvement in the etiopathogenesis of Cystic Ovarian Follicle (COF) in dairy cows. The study was conducted in 30 healthy cows (group C) and 30 cows affected by COF (group COF). The fluid of follicular cysts and of preovulatory follicles was drawn by means of ultrasound guided aspiration from the cows of both groups. The fluid obtained was analyzed by a photometric analytical system to detect ROS level. ROS concentration was statistically lower in the cystic fluid than in the follicular one (62.4 ± 13.36 U.Carr vs. 84.89 ± 26.99 U.Carr) (p<0.05), thus suggesting that an alteration of the cascade responsible for ROS production may be implicated in the complex etipathogenesis of COF.

Oxidative Stress in Neonatology. A Review

Free radicals are highly reactive oxidizing agents containing one or more unpaired electrons. Both in human and veterinary neonathology, it is generally accepted that oxidative stress functions as an important catalysator of neonatal disease. Soon after birth, many sudden physiological and environmental conditions make the newborn vulnerable for the negative effects of oxidative stress, which potentially can impair neonatal vitality. As a clinician, it is important to have in depth knowledge about factors affecting maternal/neonatal oxidative status and the cascades of events that enrol when the neonate is subjected to oxidative stress. This report aims at providing clinicians with an up-to-date review about oxidative stress in neonates across animal species. It will be emphasized which handlings and treatments that are applied during neonatal care or resuscitation can actually impose oxidative stress upon the neonate. Views and opinions about maternal and/or neonatal antioxydative therapy will be shared.

Tyrosine kinase inhibitors (TKIs) in human and pet tumours with special reference to breast cancer: A comparative review

Tyrosine kinase receptors (TKRs) play a key role in tumour cell proliferation and survival since they are involved in endothelial cell activation leading to tumour neoangiogenesis. In particular, vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (c-KitR), and colony-stimulating factor 1 (CSF-1) are overexpressed or constitutively activated in human and pet malignancies. A variety of small molecule inhibitors targeting specific tyrosine kinases (known as tyrosine kinase inhibitors or TKIs) have recently been approved, or are under investigation, for the treatment of human cancer. TKI application in animal cancer is however relatively recent. This review aims to illustrate the major aspects of tyrosine kinase dysfunctions, with special regard to human and animal cancer of the mammary gland, providing an update on the background of the anti-angiogenic and anti-neoplastic properties of TKIs in human and veterinary cancer.

First Demonstration of an Increased Serum Level of Reactive Oxygen Species During the Peripartal Period in the Ewes

Reactive Oxygen Species (ROS) are produced during oxidative metabolism, and regulate many biological processes. The acute inflammation characterizing parturition induces many physiological changes. Among them, there is evidence that ROS affect the synthesis of many factors involved in parturition. Our study aims to determine serum levels of ROS in periparturient ewes, as well as to establish a value of reference of their physiological concentration. ROS determination was performed on blood collected every 12 hours in periparturient twin pregnant ewes. Our results will show a significant increase in ROS concentrations from the beginning to the end of the experiment. This increase may be due to the inflammatory process establishing during parturition.

Localization of thyrotropin receptor and thyroglobulin in the bovine corpus luteum

The receptor of the Thyroid Stimulating Hormone (TSHr) and thyroglobin (TGB), are two proteic factors necessary for the synthesis of hormones, in the thyrocite. In mammals, many immuno-histochemical reports indicate the presence of the TSHr in extra-thyroidal tissues, but not in the ovary. Triiodothyronine (T(3)) and thyroxine (T(4)) have been widely shown to affect ovarian functions and the synthesis of progesterone (P(4)). The aim of this study was to determine if by immunohistochemistry techniques TSHr and TGB could be found in the bovine corpora haemorragica, lutea and albicantia. A primary rabbit polyclonal antibody against human TSHr and a primary rabbit polyclonal antibody against human TGB were employed. Furthermore, the accuracy of bovine thyroid to the antibodies used in this study was tested. A positivity reaction for the anti-TSHr serum in the large luteal cells and immunostaining of both small and large luteal cells with the anti-TGB serum occurred only in mature corpora lutea. No immunostaining was detected in stromal cells, blood and lymphatic vessels and in corpora haemorragica and albicantia. Bovine thyroid tissue showed immunostaining to both the antibodies employed. These data suggest that the luteal cells of mature corpora lutea may be involved in the synthesis of thyroid hormones, which may modulate P(4) synthesis, acting in an autocrine and paracrine way.

Peritoneal adhesions in human and veterinary medicine: from pathogenesis to therapy. A review

Any peritoneal inflammatory process consequent to infections or surgical injuries may induce abdominal adhesion formation. Peritoneal adhesions are connective laciniae that develop among abdomino-pelvic organs that limit physiologic visceral motion. Consequently, fertility may be impaired, and intestinal obstruction and pelvic pain may develop, mainly in subjects that had undergone gynaecological surgery. This review illustrates the pathogenic steps of adhesiogenesis and the therapeutic scenario that evolved over the years to tackle the threat of peritoneal adhesions, both in domestic animals and in women.

Evaluation of blood and milk oxidative status during early postpartum of dairy cows

In dairy cows, the intensity of metabolic activity, associated with the negative energy balance (NEBAL), is responsible for an increased production of reactive oxygen species (ROS) and, subsequently, for the development of the condition of oxidative stress, which may overwhelm the antioxidant potential of the bovine maternal organism, making it prone to the development of many puerperal dysfunctions, as well as to an alteration of colostrum and milk quality. Given these premises, the aims of this study are to evaluate serum and milk concentrations of ROS and lipoperoxides, vitamins A and E, on the 10th, 12th, 14th and 16th day postpartum of dairy cows, a particularly critical period during which the NEBAL reaches its nadir, and to compare the trends of these parameters in two different bovine breeds. The study was performed in pluriparous Italian Friesian and Brown dairy cows. On the 10th day postpartum, all cows underwent a clinical examination to exclude the presence of alterations; furthermore, on the same day, a milk sample was collected from each cow, in order to perform the somatic cell count (SCC; (CE) N. 853/2004) and to establish which of them had an SCC ≤400,000/ml or >400,000/ml. In this study, among the 110 cows that were initially selected, the evaluation of these parameters allowed the inclusion of 80 animals, which were divided into four groups of 20 subjects each: Group F and F1: Italian Friesian healthy cows, with SCC ≤400,000/ml and >400,000/ml, respectively; Group B and B1: Italian Brown healthy cows, with SCC ≤400,000/ml and >400,000/ml, respectively. On the 10th, 12th, 14th and 16th day postpartum, peripheral blood and milk samples were collected. The results obtained show that in group B1 there were higher concentrations of ROS and milk antioxidants compared with Friesian group cows. This datum let us suppose that even in the presence of higher ROS concentrations the antioxidant status found in group B1 seems to be able to counteract the oxidative damage, which is more likely to develop in these cows.

Bovine ovarian follicular cysts: in vitro effects of lecirelin, a GnRH analogue

This study investigates the mechanisms of action by which a GnRH analogue may modulate the contractility of the bovine ovarian follicular wall. The in vitro evaluation of the spontaneous basal contractility of bovine preovulatory and cystic follicles was performed, followed by testing the effects of lecirelin, a GnRH analogue, on their basal contractility. Strips of tissue in isolated organ bath were employed. In addition, to better investigate the mechanism of action of lecirelin, the study of the effects of cumulative doses of nifedipine (a calcium channel blocker), phentolamine (an α-adrenoceptor antagonist) and reserpine (an inhibitor of the vesicular up-take of catecholamines) alone and, at the highest doses employed, associated to lecirelin, was set up. The results demonstrate that in basal conditions and after the addition of lecirelin, the strips from preovulatory follicles contract significantly more than strips from cysts. Furthermore, among the patterns of contractility evoked by the three drugs employed, the one induced by nifedipine was the only one unaffected by the addition of lecirelin. The data obtained provide the hypothesis that one of the main mechanisms of action of GnRH, could involve calcium channels.

Renin and ovarian vascularization in cows with follicular cysts after epidural administration of a GnRH analogue

The ovarian renin-angiotensin system may play an important role in follicular growth and maturation, as well as in the process of ovulation. The aim of this study was to investigate the effects of administration of a GnRH analogue to cows with ovarian follicular cysts on plasma renin concentrations and ovarian vascularization. This study was performed with 60 Friesian cows, which were diagnosed with follicular cysts, and randomly allocated into two groups: group A (treatment; n=30) received 2ml of lecirelin (Dalmarelin((R)) - Fatro), per head via sacro-coccygeal epidural, and group B (control; n=30) received 2ml saline solution (0.9% NaCl) per head by the same route. Blood samples were immediately collected prior to administration (T0) and then 24h (T1), 48h (T2) and 8 days (T3) after administration of the treatment, for both groups. Ovarian vascularization was evaluated utilizing Power Doppler on these same days in 10 animals from each group. The number of pixels detected by Power Doppler was used as an indicator of the degree of vascularization. Plasma renin concentrations remained relatively constant for the control (group B) animals, but increased as the sampling period progressed (NS) for the treated cows (group A). Similarly, there were no changes in ovarian vascularization (number of pixels) for the control cows, but vascularization increased throughout the sampling period in the treated animals. The number of pixels associated with cysts was significantly higher for treated compared to control cows at 24h after treatment (P<0.001). The epidural administration of a GnRH analogue was determined to be a highly effective therapy for follicular cysts (regression occurred in 82% of treated cows within 8+/-2 days after treatment, but in none of the control cows), which also enhanced ovarian vascularization.