Primary cell cultures for understanding rat epididymal inflammation.

Treatment-induced epididymal inflammation and granuloma formation is only an occasional problem in preclinical drug development, but it can effectively terminate the development of that candidate molecule. Screening for backup molecules without that toxicity must be performed in animals (generally rats) that requires at least 2 to 3 weeks of in vivo exposure, a great deal of specially synthesized candidate compound, and histologic examination of the target tissues. We instead hypothesized that these treatments induced proinflammatory gene expression, and so used mixed-cell cultures from the rat epididymal tubule to monitor the induction of proinflammatory cytokines.

Maternal-placental insulin-like growth factor (IGF) signaling and its importance to normal embryo-fetal development.

As background for an antibody-based therapeutic program against the IGF receptor, we undertook a review of available information on the early pregnancy-specific regulation and localization of IGFs, IGF-binding proteins (BPs), IGFBP-specific proteases, and the type 1 IGF receptor relative to placental maintenance, function of placental nutrient transporters, placental cellular differentiation/turnover/apoptosis, and critical hormone signaling needed to maintain pregnancy. Possible adverse outcomes of altered IGF signaling include prenatal loss, fetal growth retardation, and maldevelopment are also discussed. It appears that the IGF axes in both the conceptus and mother are important for normal embryo-fetal growth.

Assessment of the Embryonic Stem Cell Test and application and use in the pharmaceutical industry.

Background: The European Centre for the Validation of Alternative Methods (ECVAM) designed the Embryonic Stem Cell Test (EST) as a tool for classifying developmentally toxic compounds. An in vitro tool to assess developmental toxicity would be of great value to the pharmaceutical industry to help with toxicity-associated attrition.

Methods: ECVAM's EST protocol was used, but employing a different mouse embryonic stem cell (ESC) line and an alternative differentiation medium.

Struggles for equivalence: in vitro developmental toxicity model evolution in pharmaceuticals in 2006.

Our group has been using the ECVAM Embryonic Stem Cell assay to predict developmental toxicity. In order to improve the separation of non-teratogens from weak teratogens, we have employed measures of gene expression, and different statistical methods from those originally used to develop the test. These approaches have fundamentally not improved the discrimination of 'weaks' from 'nons'.

Antisense modulation of the coding or regulatory sequence of the folate receptor (folate binding protein-1) in mouse embryos leads to neural tube defects.

Background: Although folic acid decreases the incidence of neural tube defects (NTDs) in humans, the mechanism for this protection is unknown. We have employed antisense technology to alter expression of the gene for the folate receptor (folate binding protein-1 [Folbp1]) in mouse embryos cultured in vitro.

Methods: Embryos were explanted on day 8 of gestation and cultured for 44 hr.

Rat embryos express transcripts for cyclooxygenase-1 and carbonic anhydrase-4, but not for cyclooxygenase-2, during organogenesis.

Background: Acetylsalicylic acid (ASA) is a rat teratogen, and exposures on gestational days (GDs) 9 and 10 induce diaphragm, cardiac, and midline defects. ASA inhibits members of the cyclooxygenase (COX) family and potentially members of the carbonic anhydrase (CA) family. The objective of this study was to determine whether the mRNA developmental expression pattern for any COX or CA isoform was consistent with a model in which ASA teratogenicity is mediated through direct interaction with one of these enzymes within embryos or within the adjacent ectoplacental cone (EPC) or yolk sac.