Hyaluronic acid and epidermal growth factor improved the bovine embryo quality by regulating the DNA methylation and expression patterns of the focal adhesion pathway

Focal adhesion pathway is one of the key molecular pathways affected by suboptimal culture conditions during embryonic development. The epidermal growth factor (EGF) and hyaluronic acid (HA) are believed to be involved in the focal adhesion pathway function by regulating the adherence of the molecules to the extracellular matrix. However, regulatory and molecular mechanisms through which the EGF and HA could influence the embryo development is not clear. Therefore, this study aimed to investigate the effect of continued or stage specific supplementation of EGF and/or HA on the developmental competence and quality of bovine preimplantation embryos and the subsequent consequences on the expression and DNA methylation patterns of genes involved in the focal adhesion pathway. The results revealed that, the supplementation of EGF or HA from zygote to the blastocysts stage reduced the level of reactive oxygen species and increased hatching rate after thawing. On the other hand, HA decreased the apoptotic nuclei and increased blastocyst compared to EGF supplemented group. Gene expression and DNA methylation analysis in the resulting blastocysts indicated that, combined supplementation of EGF and HA increased the expression of genes involved in focal adhesion pathway while supplementation of EGF, HA or a combination of EGF and HA during the entire preimplantation period changed the DNA methylation patterns of genes involved in focal adhesion pathway. On the other hand, blastocysts developed in culture media supplemented with EGF + HA until the 16-cell stage exhibited higher expression level of genes involved in focal adhesion pathway compared to those supplemented after the 16-cell stage. Conversely, the DNA methylation level of candidate genes was increased in the blastocysts obtained from embryos cultured in media supplemented with EGF + HA after 16-cell stage. In conclusion, supplementation of bovine embryos with EGF and/or HA during the entire preimplantation period or in a stage specific manner altered the DNA methylation and expression patterns of candidate genes involved in the focal adhesion pathway which was in turn associated with the observed embryonic developmental competence and quality.

Effect of host portal and peripheral sera fractions on cell proliferation of Schistosoma mansoni schistosomules

Schistosomules of Schistosoma mansoni were incubated in medium containing hamster (highly susceptible host) portal or peripheral venous serum, or rat (poorly susceptible host) portal or peripheral venous serum or their fractions in the presence of bromodeoxyuridine (BrdU) in order to determine effects of host sera on cell proliferation. BrdU labeling indices (BLIs) were significantly increased in the presence of portal (33.05±0.70, p<0.05), but not in peripheral serum (19.1±0.85, p>0.05) of hamsters, compared to schistosomules cultured in presence of control medium (18.96±0.66). This stimulatory effect was substantially reproduced by fraction 4 (31.03±0.69, p>0.05) separated from hamster portal serum. In contrast, no significant differences were observed in the BLIs in rat portal or peripheral sera as well as their fractions when compared to control medium. Taken together, it was concluded that portal serum of hamster and its fraction which includes a low molecular weight protein (20 kDa) enhanced cell proliferation of S. mansoni schistosomules. This could explain the localization and preference of S. mansoni schistosomules and worms to portal-mesenteric venous system.

Human portal serum stimulates cell proliferation in immature Schistosoma mansoni

Schistosomula of Schistosoma mansoni were incubated in RPMI 1640 medium containing 10% fetal calf serum, 10% human portal venous or 10% human peripheral venous sera in the presence of bromodeoxyuridine (BrdU) in order to measure differences in cell proliferation. The rates of cell proliferation as expressed by BrdU labelling indices (BLI) were determined as a function of time of incubation by immunohistochemistry using monoclonal antibody to BrdU. Compared to schistosomula cultured in the presence of RPMI plus 10% fetal calf serum, BLIs were increased by 60% in the presence of human portal, but not in peripheral serum. This stimulatory effect was substantially reproduced by a fraction of portal serum with a molecular weight range between 1 and 50 kDa. However, in the presence of human peripheral venous serum, either whole or fractionated, schistosomula showed no significant difference compared to RPMI plus 10% fetal calf serum alone. Furthermore, human portal serum fractions of molecular weight greater than 50 kDa also revealed no significant difference relative to control. The results indicate that portal venous serum component(s) of a molecular weight range higher than most simple nutrients can greatly stimulate the rate of cell proliferation of Schistosoma mansoni schistosomula.

Serum and urinary amino acid pattern in schistosomal infection among Egyptians

The amino acid pattern in plasma and urine of Bilharzial Egyptian patients with different degrees of complications was investigated. The results obtained showed that in mansoniasis, accumulation of amino acids in the circulation is due to derangement in liver function which retards the utilization of amino acids in protein synthesis particularly in the advanced stage of the disease. This is also in part due to liver cell degeneration which parallel the severity of the infection. Aminoaciduria in haematobiasis is partly an overflow type, while in severe cases urinary tract tissue degeneration may be a participating factor. Aminoaciduria in haematobiasis is due to haematuria and urinary tract tissue degeneration.