Gestational diabesity and foetoplacental vascular dysfunction

Gestational diabetes mellitus (GDM) shows a deficiency in the metabolism of D-glucose and other nutrients, thereby negatively affecting the foetoplacental vascular endothelium. Maternal hyperglycaemia and hyperinsulinemia play an important role in the aetiology of GDM. A combination of these and other factors predisposes women to developing GDM with pre-pregnancy normal weight, viz. classic GDM. However, women with GDM and prepregnancy obesity (gestational diabesity, GDty) or overweight (GDMow) show a different metabolic status than women with classic GDM. GDty and GDMow are associated with altered l-arginine/nitric oxide and insulin/adenosine axis signalling in the human foetoplacental microvascular and macrovascular endothelium. These alterations differ from those observed in classic GDM. Here, we have reviewed the consequences of GDty and GDMow in the modulation of foetoplacental endothelial cell function, highlighting studies describing the modulation of intracellular pH homeostasis and the potential implications of NO generation and adenosine signalling in GDty-associated foetal vascular insulin resistance. Moreover, with an increase in the rate of obesity in women of childbearing age worldwide, the prevalence of GDty is expected to increase in the next decades. Therefore, we emphasize that women with GDty and GDMow should be characterized with a different metabolic state from that of women with classic GDM to develop a more specific therapeutic approach for protecting the mother and foetus

Binding of primitive hematopoietic progenitor cells to marrow stromal cells involves heparan sulfate

Abstract Blast colony-forming cells (BI-CFC) and pre-colony-forming unit- granulocyte, monocyte (CFU-GM) in human bone marrow bind to marrow- derived stromal layers grown in the presence of methylprednisolone (MP+), but do not bind to stroma grown without MP (MP-). The BI-CFC bind to stroma and form colonies when overlaid with agar; the pre-CFU- GM bind to stroma and release CFU-GM into the supernatant culture medium (delta assay). These two classes of progenitor may represent similar stages of hematopoietic cell development. Their binding to stroma depends on the presence of heparan sulfate proteoglycan (HS-PG) in the extracellular matrix secreted by the stromal cells. Here, we have analyzed the functional and biochemical properties of HS-PG isolated from MP+ and MP- stromal cultures. HS-PG or isolated HS glycosaminoglycan (GAG) side chains partially blocked progenitor cell binding when they were added to the 2-hour binding phase of the BI-CFC or delta assays. Gel electrophoresis of HS-PG resolved more bands in matrix preparations from MP+ cultures than in preparations from MP- cultures. The blocking activity of the eluted MP+ HS-PG bands depended partly on the amount of GAG attached to the protein core and presumably partly on the structure of the core itself. Time course studies demonstrated that the HS-dependent phase of the binding interaction was limited to the first 30 to 60 minutes of the 2-hour binding phase. The different blocking effects of MP+ and MP- HS indicate that they have different biochemical properties. The HS-GAG in MP+ stroma has a higher degree of sulfation and a greater negative charge to mass ratio compared with MP- HS-GAG. Variations in HS may determine specific binding by hematopoietic progenitor cells and a heparan sulfate receptor is envisaged as acting in concert with further cell adhesion molecules (CAMs) on the progenitor cell surface.</jats:p

Binding of primitive hematopoietic progenitor cells to marrow stromal cells involves heparan sulfate

Blast colony-forming cells (BI-CFC) and pre-colony-forming unit- granulocyte, monocyte (CFU-GM) in human bone marrow bind to marrow- derived stromal layers grown in the presence of methylprednisolone (MP+), but do not bind to stroma grown without MP (MP-). The BI-CFC bind to stroma and form colonies when overlaid with agar; the pre-CFU- GM bind to stroma and release CFU-GM into the supernatant culture medium (delta assay). These two classes of progenitor may represent similar stages of hematopoietic cell development. Their binding to stroma depends on the presence of heparan sulfate proteoglycan (HS-PG) in the extracellular matrix secreted by the stromal cells. Here, we have analyzed the functional and biochemical properties of HS-PG isolated from MP+ and MP- stromal cultures. HS-PG or isolated HS glycosaminoglycan (GAG) side chains partially blocked progenitor cell binding when they were added to the 2-hour binding phase of the BI-CFC or delta assays. Gel electrophoresis of HS-PG resolved more bands in matrix preparations from MP+ cultures than in preparations from MP- cultures. The blocking activity of the eluted MP+ HS-PG bands depended partly on the amount of GAG attached to the protein core and presumably partly on the structure of the core itself. Time course studies demonstrated that the HS-dependent phase of the binding interaction was limited to the first 30 to 60 minutes of the 2-hour binding phase. The different blocking effects of MP+ and MP- HS indicate that they have different biochemical properties. The HS-GAG in MP+ stroma has a higher degree of sulfation and a greater negative charge to mass ratio compared with MP- HS-GAG. Variations in HS may determine specific binding by hematopoietic progenitor cells and a heparan sulfate receptor is envisaged as acting in concert with further cell adhesion molecules (CAMs) on the progenitor cell surface.</jats:p

Interferon-alpha overrides the deficient adhesion of chronic myeloid leukemia primitive progenitor cells to bone marrow stromal cells

Abstract Primitive blast colony-forming cells (BI-CFC) from chronic myeloid leukemia (CML) patients are defective in their attachment to bone marrow-derived stromal cells compared with normal BI-CFC. We investigated the effect of recombinant interferon-alpha 2a (IFN-alpha) on this interaction between hematopoietic progenitor cells and bone marrow-derived stromal cells by culturing normal stromal cells with IFN- alpha (50 to 5,000 U/mL). At 50 U/mL we found that: (1) the capacity of stromal cells to bind two types of CML primitive progenitor cells (BI- CFC and long-term culture-initiating cells) was increased; and (2) the amount of sulfated glycosaminoglycans (GAGs) in the stromal layer was increased. However, sulfated GAGs were not directly involved in binding CML BI-CFC, unlike binding by normal BI-CFC, which is sulfated GAG- dependent. Neuraminidase-treated control stromal cells bound an increased number of CML BI-CFC, reproducing the effect of IFN-alpha, whereas the binding to IFN-alpha-treated stromal cells was unaffected by neuraminidase treatment. Thus, the enhanced attachment by primitive CML progenitor cells to INF-alpha-treated stromal cells might be due to changes in the neuraminic acid composition in the stromal cell layer. Our in vitro evidence may provide insights into the mechanism of action of IFN-alpha in vivo. Prolonged administration may alter the marrow microenvironment in some patients such that it can restrain the aberrant proliferation of Philadelphia chromosome (Ph)-positive stem cells while permitting Ph-negative stem cells to function normally.</jats:p

Interferon-alpha overrides the deficient adhesion of chronic myeloid leukemia primitive progenitor cells to bone marrow stromal cells

Primitive blast colony-forming cells (BI-CFC) from chronic myeloid leukemia (CML) patients are defective in their attachment to bone marrow-derived stromal cells compared with normal BI-CFC. We investigated the effect of recombinant interferon-alpha 2a (IFN-alpha) on this interaction between hematopoietic progenitor cells and bone marrow-derived stromal cells by culturing normal stromal cells with IFN- alpha (50 to 5,000 U/mL). At 50 U/mL we found that: (1) the capacity of stromal cells to bind two types of CML primitive progenitor cells (BI- CFC and long-term culture-initiating cells) was increased; and (2) the amount of sulfated glycosaminoglycans (GAGs) in the stromal layer was increased. However, sulfated GAGs were not directly involved in binding CML BI-CFC, unlike binding by normal BI-CFC, which is sulfated GAG- dependent. Neuraminidase-treated control stromal cells bound an increased number of CML BI-CFC, reproducing the effect of IFN-alpha, whereas the binding to IFN-alpha-treated stromal cells was unaffected by neuraminidase treatment. Thus, the enhanced attachment by primitive CML progenitor cells to INF-alpha-treated stromal cells might be due to changes in the neuraminic acid composition in the stromal cell layer. Our in vitro evidence may provide insights into the mechanism of action of IFN-alpha in vivo. Prolonged administration may alter the marrow microenvironment in some patients such that it can restrain the aberrant proliferation of Philadelphia chromosome (Ph)-positive stem cells while permitting Ph-negative stem cells to function normally.</jats:p