Placental immunopathology in the FIV-infected cat: a role for inflammation in compromised pregnancy?

Molecular Factors Involved in the Reproductive Morphophysiology of Female Domestic Cat (Felis catus)

The domestic cat (Felis catus) is considered an important model for the study of feline reproductive morphophysiology. However, although the morphological changes and clinical signs that occur during the estrous cycle and pregnancy are well known, little is known about the molecular mechanisms involved in the reproductive physiology of this animal species. Thus, this paper reviews the current knowledge about the modulation and expression profile of hormonal, immunological, redox, and growth mediators involved in the uterine, ovarian, and placental morphophysiology of domestic cats.

Pathology of Perinatal Disorders

Perinatal deaths including abortions, stillbirths, and neonatal deaths are an important economic and emotional challenge for companion animal owners, breeders, and veterinarians. A protocol for the investigation of perinatal deaths in dogs and cats is described, including examination of the placenta. Specific lesions of common infectious diseases leading to perinatal death are presented, as well as the more prevalent noninfectious causes. These include viruses, bacteria, protozoa, metabolic causes, "accidents of pregnancy," nutritional deficiencies, intoxications, hormonal causes, and heritable and nonheritable congenital defects.

Sildenafil (Viagra®) blocks inflammatory injury in LPS-induced mouse abortion: A potential prophylactic treatment against acute pregnancy loss?

INTRODUCTION

Recurrent pregnancy losses (RPL) are common women's health issues. Inflammatory and thrombotic events have been associated with RPL including excessive production of cytokines, in particular TNF-α. However, mechanisms behind gestational losses are not yet fully understood. Sildenafil inhibits phosphodiesterase Type-5 (PDE5). This drug increases intracellular cyclic guanosine monophosphate, having vasodilatory and, more recently described, anti-inflammatory properties. PDE5 is present in murine and human uterus and placenta. Sildenafil is already used clinically for treatment of human fetal growth restriction (FGR). Our objective was to determine if Sildenafil alone or in combination with Heparin had protective effects in pregnant Swiss albino challenged to abort by lipopolysaccharide (LPS).

METHODS

Treatments (Sildenafil (50 mg/kg/day), Heparin (500 IU/Kg/day) or Sildenafil + Heparin at the same doses) were initiated the morning of copulation plug detection (gestational day (gd0)). On the 15th day of pregnancy, an intra-peritoneal injection of LPS (100 μg/kg) was administered. Untreated, pregnant mice challenged by LPS served as controls.

RESULTS

Assessments at 48 h after LPS revealed that Sildenafil + Heparin prevented fetal loss. Early assessments at 2 h after LPS indicated that the pretreatments prevented induction of inflammatory cytokine production (TNF-α, IL-1β/NF-κβ) and preserved placental histopathology.

DISCUSSION

Combined Sildenafil + Heparin therapy was superior to either treatment alone in most analyses. The known safety of Sildenafil and Heparin in human pregnancy suggests that usage of these combined agents may be of value for treatment of patients with impending pregnancy loss or prophylactically in women with a history of recurrent miscarriages.

Role of the placenta in adverse perinatal outcomes among HIV-1 seropositive women

Women seropositive for human immunodeficiency virus type 1 (HIV-1) are at an increased risk for a number of adverse perinatal outcomes. Although efforts to reduce mother-to-child transmission of HIV (MTCT) remain a priority in resource-limited countries, HIV testing and treatment have led to steep declines in MTCT in well-resourced countries. Even so, HIV seropositive pregnant women in the United States continue to deliver a disproportionately high number of preterm and low birth weight infants. In this mini-review, we address the role of the placenta in such HIV-related perinatal sequelae. We posit that adverse perinatal outcomes may result from two mutually non-exclusive routes: (1) HIV infection of the placenta proper, potentially leading to impaired maternal-fetal exchange; and (2) infection of the maternal decidual microenvironment, possibly disrupting normal placental implantation and development. Further research into the relationship between HIV-1 infection and placental pathology may lead to the development of novel strategies to improve birth outcomes among HIV-1 seropositive parturients.

FIV in cats--a useful model of HIV in people?

The feline immunodeficiency virus (FIV) shares genomic organization, receptor usage, lymphocyte tropism, and induction of immunodeficiency and increased susceptibility to cancer with the human immunodeficiency virus (HIV). Global distribution, marked heterogeneity and variable host adaptation are also properties of both viruses. These features render the FIV-cat model suitable to explore many aspects of lentivirus-host interaction and adaptation, and to explore treatment and prevention of infection. Examples of fundamental discoveries that have emerged from study in the FIV-cat model concern two-receptor entrance strategies that target memory T-lymphocytes, host factors that restrict retroviral infection, viral strategies for replication in non-dividing cells, and identification of correlates of immunity to the virus. This article provides a brief overview of strengths and limitations of the FIV-cat model for comparative biology and medicine.