Vasoactive intestinal peptide shortens both G1 and S phases of neural cell cycle in whole postimplantation cultured mouse embryos.

Vasoactive intestinal peptide, a trophic and mitogenic factor, stimulates growth in whole cultured mouse embryos. Inhibition of this growth function between embryonic days 9 and 11 induces growth retardation accompanied by severe microcephaly. In the present study, to determine the effects of this peptide on the different phases of the cell cycle of neural cells, embryonic day 9.5 cultured mouse embryos were cumulatively labelled with bromodeoxyuridine. Vasoactive intestinal peptide (10(-7)M) shortened S phase and G1 phase of neuroepithelial cells by 50% (4.8-2.4 h) and 58% (1.9-0.8 h), respectively, compared with controls. G2 and M phases were not modified by vasoactive intestinal peptide treatment. Total cell cycle length was consequently reduced by 43% (8.2-4.7 h) in vasoactive intestinal peptide treated embryos, compared with controls. In contrast, vasoactive intestinal peptide did not modify the rate of neuroepithelial cell death as assessed by the proportion of nuclei containing fragmented DNA. These data suggest that vasoactive intestinal peptide stimulates growth in premigratory stages of nervous system development by shortening S and G1 phases of the cell cycle and that S phase duration can be regulated by a physiological peptide.

Growth factor properties of VIP during early brain development. Whole embryo culture and in vivo studies.

Vasoactive intestinal peptide (VIP), a 28 amino acid neuropeptide widely distributed in the mammalian nervous system, has potent growth-related actions that influence cell division, neuronal survival, and neurodifferentiation. To address the potential effects of VIP on embryonic growth, whole postimplantation embryo cultures were used. After a 4-hour incubation, VIP stimulated growth as assessed by the following increases from control: embryonic volume (63%), DNA (103%), and protein content (63%), as well as the number of cells in S-phase (490%). No apparent histological abnormalities are produced by VIP. To assess the in vivo function of VIP in early CNS growth, a VIP antagonist (VA) was injected i.p. between E9 and E11. VA induced a dose reduction of the DNA (84% of controls) and protein (80% of controls) contents of the E11 head and a decrease of E17 brain weight (87% of controls). In contrast, body growth was less affected by the antagonist. injections of VA for a longer period (E9 to E17) did not increase the severity of the microcephaly. By ex vivo autoradiography, GTP-sensitive VIP binding sites were detected in the germinative neuroepithelium between E9 and E11, but not between E13 and E15, during neuronal migration. These data demonstrate that VIP regulates mitogenic activity in the premigratory neuroepithelium. Although this effect is limited to a short ontogenic period, blockade of VIP by a specific antagonist induces a severe microcephaly.

Severe microcephaly induced by blockade of vasoactive intestinal peptide function in the primitive neuroepithelium of the mouse.

Vasoactive intestinal peptide (VIP) has potent growth-related actions that influence cell mitosis, neuronal survival, and neurodifferentiation in cell culture. VIP can also produce dramatic growth in postimplantation mouse embryos in vitro, characterized by large increases in cell number. The goal of the present study was to assess the role of VIP on early nervous system development in vivo. Pregnant mice were treated with a specific antagonist to VIP. Prenatal administration of the antagonist early in development (E9-E11) produced severe microcephaly characterized by decreased embryonic brain weight with reduced DNA and protein content. The retardation of growth was disproportionally manifested in the brain compared with the body and was prevented by co-treatment with VIP. Identical treatment with the antagonist later in gestation had no detectable effect on embryonic growth. VIP receptors, which were restricted to the central nervous system during this stage of embryonic development, were increased in the neuroepithelium of antagonist-treated embryos while the number of cells in S-phase was significantly decreased. Thus, VIP regulates brain growth in vivo and inhibition of its action provides new insight into a molecular mechanism for microcephaly.

Histologic study of peritoneal endometriosis in infertile women.

The present study included 118 patients undergoing a laparoscopy for infertility. In 86 patients with laparoscopically diagnosed endometriosis (group I), biopsies were taken from areas of apparent endometriosis (n = 86) and from a visually normal peritoneum (n = 52). Histology reveals the presence of endometriosis in 93% of positive sites and in 13% of negative sites. In 32 patients without endometriosis at laparoscopy (group II), biopsies were taken from normal uterosacral ligaments (n = 32). Endometriosis was observed in 6% of cases. Despite the increased ability to detect pigmented and nonpigmented endometriotic lesion, histological study revealed the presence of endometriosis in normal peritoneum in 13% (group I) and 6% (group II) of cases.