Biomedical subjects

G Rajashekhar

Publications and source records attributed to G Rajashekhar.

3 recordsLinked to original sources

PubMed2003

Over-expression and secretion of angiogenin in intrauterine growth retardation placenta.

Human angiogenin is a potent inducer of neovascularization. There is a strong evidence to suggest that it might be involved in morphological and angiogenic changes in the placenta, that are necessary for a successful fetal outcome during pregnancy. However, its precise role in the pathogenesis of abnormal pregnancies is yet unknown. Intrauterine growth retardation (IUGR), an abnormal pregnancy is not a specific disease entity per se, but rather a manifestation of many possible fetal and maternal disorders. In this study, we demonstrated, for the first time, that placental explants in vitro secrete significantly elevated levels of angiogenin in placental tissues from patients with IUGR. We also observed enhanced mRNA expression in placenta from these patients. In addition, using the immunohistochemical methods, we observed identical staining of angiogenin to villous syncytiotrophobalst and fetal endothelial cells in both IUGR and normal placenta. Functionally active placental explants were used to detect immunoreactive angiogenin in conditioned media of all the samples from IUGR placenta and normal term group. The mean levels of angiogenin secreted by IUGR placenta were 1.4-, 1.6-, and 1.3-fold higher (P < 0.01) than normal term samples at 24, 48, and 72 hr of culture, respectively. Expression profiles of angiogenin from term and IUGR cases are in agreement with its mRNA levels and immunoblot analysis. In conclusion, the significant elevated levels of angiogenin in IUGR placenta may provide a molecular mechanism for the abnormal placental development.

Female↗

PubMed2003

Expression and secretion of the vascular cell adhesion molecule-1 in human placenta and its decrease in fetal growth restriction.

OBJECTIVE: The vascular cell adhesion molecule-1 (VCAM-1) is a member of the immunoglobulin gene superfamily and is expressed principally on endothelial cells. The present study was undertaken to compare the expression and secretion of VCAM-1 from normal pregnancies and those complicated by fetal growth restriction (FGR). METHODS: Placentas from first-trimester (FT) (n = 17), normal term (n = 19), and FGR (n = 16) patients were collected immediately after elective cesarean delivery. VCAM-1 mRNA expression profiles by reverse transcriptase polymerase chain reaction, protein levels by enzyme-linked immunosorbent assay using explant culture in vitro, and its cellular localization by confocal microscopy were compared between FGR and normal placentas. RESULTS: Functionally active placental explants were used to detect immunoreactive VCAM-1 in conditioned media of all the samples from the three groups. The mean levels of VCAM-1 produced by FT villi were found to be 1.9-, 1.7-, and 1.5-fold higher (P <.02) than term villi at 24, 48, and 72 hours of culture, respectively. Conversely, the respective mean levels of VCAM-1 produced by FGR placental villi were 2.3-, 2.5-, and 2.0-fold lower than levels of the normal term placental villi (P <.05). The secretion profiles of VCAM-1 from FT, term, and FGR villi correlated well with the mRNA levels; the amount secreted in FT villi was twice that of term villi. Moreover, mRNA transcripts from FGR pregnancies showed significantly decreased expression, in conformity with explant results. CONCLUSIONS: The presence of VCAM-1 in placental villi and down-regulation of its production at term indicate that VCAM-1 production is specific to developmental stage. The decreased VCAM-1 expression in FGR pregnancy could be attributed to the uteroplacental deficiency that is characteristic of this condition.

Adult↗

PubMed2002

Expression and localization of angiogenin in placenta: enhanced levels at term over first trimester villi.

Human angiogenin, a 14-kDa non-glycosylated polypeptide with both angiogenic and ribonucleolytic activities, is implicated in angiogenesis, a complex process of proliferation and formation of new capillary blood vessels from existing blood vessels. Placental growth requires extensive angiogenesis, which develops its vascular structure in both fetal chorionic villi and maternal deciduas. In this study, we investigated the expression profiles of angiogenin in placental villi from early and late gestation at both mRNA and protein levels using explant cultures in vitro followed by RT-PCR, immunoblot, and immunohistochemical analyses. From functionally active placental explants, angiogenin was detected in conditioned media of all the samples from first trimester and term group. The mean levels of angiogenin produced by term villi were found to be 2.6-, 2.1-, and 2.2-fold higher (P < 0.01) than first trimester villi at 24, 48, and 72 hr of culture, respectively. Expression profiles of angiogenin from term and first trimester villi seem to agree with its mRNA levels and immunoblot analysis; the expression in term villi was twice that in first trimester villi. The presence of angiogenin in placental villi and upregulation of its production towards term indicate that angiogenin production by the placenta is specific to the developmental stage. In conclusion, the observed changes in the localization and mRNA expression of angiogenin during placental development raise the possibility that it is involved in morphological and angiogenic changes in this endocrine organ vital to the successful fetal outcome during pregnancy.

Adult↗