Angiogenesis-Related Genes in Endothelial Progenitor Cells May Be Involved in Sickle Cell Stroke

Background The clinical aspects of sickle cell anemia (SCA) are heterogeneous, and different patients may present significantly different clinical evolutions. Almost all organs can be affected, particularly the central nervous system. Transient ischemic events, infarcts, and cerebral hemorrhage can be observed and affect ≈25% of the patients with SCA. Differences in the expression of molecules produced by endothelial cells may be associated with the clinical heterogeneity of patients affected by vascular diseases. In this study, we investigated the differential expression of genes involved in endothelial cell biology in SCA patients with and without stroke. Methods and Results Endothelial progenitor cells from 4 SCA patients with stroke and 6 SCA patients without stroke were evaluated through the polymerase chain reaction array technique. The analysis of gene expression profiling identified 29 differentially expressed genes. Eleven of these genes were upregulated, and most were associated with angiogenesis (55%), inflammatory response (18%), and coagulation (18%) pathways. Downregulated expression was observed in 18 genes, with the majority associated with angiogenesis (28%), apoptosis (28%), and cell adhesion (22%) pathways. Remarkable overexpression of the MMP1 (matrix metalloproteinase 1) gene in the endothelial progenitor cells of all SCA patients with stroke (fold change: 204.64; P=0.0004) was observed. Conclusions Our results strongly suggest that angiogenesis is an important process in sickle cell stroke, and differences in the gene expression profile of endothelial cell biology, especially MMP1, may be related to stroke in SCA patients.

Different morphological and gene expression profile in placentas of the same sickle cell anemia patient in pregnancies of opposite outcomes

IMPACT STATEMENT

Environmentally induced changes in placental morphological and molecular phenotypes may provide relevant insight towards pathophysiology of diseases. The rare opportunity to evaluate the same patient, with sickle cell anemia (SCA), in two different pregnancies, of opposite outcomes (one early onset severe preeclampsia (PE) and the other mostly non-complicated) can prove such concept. In addition, the comparison to other conditions of known placental and vascular/inflammatory involvement strengthens such findings. Our results suggest that the clinical association between SCA and PE can be supported by common pathophysiological mechanisms, but that pathways involving response to copper and triglyceride metabolism may be important drivers of the pathophysiology of PE. Future studies using in a larger number of samples should confirm these findings and explore pathways involved in the pathophysiology of PE and its relationship with SCA.

Association of Nitric Oxide Synthase and Matrix Metalloprotease Single Nucleotide Polymorphisms with Preeclampsia and Its Complications

Background

Preeclampsia is one of the leading causes of maternal and neonatal morbidity and mortality in the world, but its appearance is still unpredictable and its pathophysiology has not been entirely elucidated. Genetic studies have associated single nucleotide polymorphisms in genes encoding nitric oxide synthase and matrix metalloproteases with preeclampsia, but the results are largely inconclusive across different populations.

Objectives

To investigate the association of single nucleotide polymorphisms (SNPs) in NOS3 (G894T, T-786C, and a variable number of tandem repetitions VNTR in intron 4), MMP2 (C-1306T), and MMP9 (C-1562T) genes with preeclampsia in patients from Southeastern Brazil.

Methods

This prospective case-control study enrolled 77 women with preeclampsia and 266 control pregnant women. Clinical data were collected to assess risk factors and the presence of severe complications, such as eclampsia and HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome.

Results

We found a significant association between the single nucleotide polymorphism NOS3 T-786C and preeclampsia, independently from age, height, weight, or the other SNPs studied, and no association was found with the other polymorphisms. Age and history of preeclampsia were also identified as risk factors. The presence of at least one polymorphic allele for NOS3 T-786C was also associated with the occurrence of eclampsia or HELLP syndrome among preeclamptic women.

Conclusions

Our data support that the NOS3 T-786C SNP is associated with preeclampsia and the severity of its complications.

Influence of age on the febrile response to E. coli and S. typhimurium endotoxins in growing pullets

1. The effect of bacterial endotoxin injection was studied in growing pullets of different ages. Commercial chicks were divided into 5 groups according to age. Bacterial endotoxins (E. coli and S. typhimurium) were injected intravenously and rectal temperature was measured over a period of 300 min. 2. The results showed no significant effect of age on the febrile response induced by bacterial endotoxins, but a slight tendency towards a reduced fever peak was observed with increasing age. The response latency also increased with age.

Effects of T cells and monocytes on globin chain synthesis in erythroid bursts cultured from human peripheral blood burst-forming units (BFU-e)

Globin chain synthesis was studied in mature erythroid bursts cultured from the peripheral blood null cells of 21 normal individuals. Although coculture of autologous T-lymphocytes with null cells resulted in a fivefold increase in the yield of erythroid bursts, the proportion of gamma chains synthesized (gamma/gamma + beta) was not significantly different from that seen without T cells. Coculture with autologous monocytes also resulted in increased burst-forming unit (BFU-e) proliferation but the ratio gamma/gamma + beta (0.25 +/- 0.03) was significantly higher than that seen with null cells alone (0.08 +/- 0.006) or with T cells (0.10 +/- 0.008). The relative increase in gamma-chain synthesis correlated with the severity of megaloblastic changes in erythroid progeny of BFU-e (P less than 0.01) but showed no significant relationship to the extent of colony maturation assessed by erythroblast maturity.

The mechanism of the anaemia in rheumatoid arthritis: effects of bone marrow adherent cells and of serum on in-vitro erythropoiesis

Clonal assays for erythroid progenitors (BFU-e and CFU-e) were used to study 20 patients with rheumatoid arthritis, 15 of whom had anaemia of chronic disease and five of whom were haematologically normal. The numbers of bone marrow BFU-e and CFU-e in the anaemic patients did not differ significantly from those in normal controls. Macrophages were removed from the bone marrow by a combination of adherence and buoyant density centrifugation over a sucrose gradient and the resulting fractions were cultured alone or together with autologous adherent cells in BFU-e assays. Co-culture with adherent cells significantly increased colony growth in both the controls and in seven of eight anaemic patients studied. Serum from 14 anaemic patients and from five non-anaemic patients was added to cultures of bone marrow or to control peripheral blood 'null' cells. Anaemic serum uniformly either inhibited or failed to stimulate BFU-e growth under these conditions. Serum from non-anaemic patients and from 10 healthy controls stimulated BFU-e growth from 'null' cells to an equal degree.

Megaloblastic change is a feature of colonies derived from an early erythroid progenitor (BFU-E) stimulated by monocytes in culture

The morphology of stained preparations of cells from human bone marrow and peripheral blood erythroid colonies cultured in methylcellulose, were examined by light microscopy. Although the morphology of 7 d erythroid colonies (CFU-E) was largely normoblastic, bone marrow and peripheral blood erythroid burst (BFU-E) showed a variable degree of megaloblastic and culture system and the deoxyuridine suppression test demonstrated active thymidine synthesis. Megaloblastic morphology was correlated with the growth induced by the addition of monocytes to erythroid progenitors. It was concluded that megaloblastosis was a feature of the erythroblasts derived from an early BFU-E which required monocytes for their development.

Erythroid colony growth in vitro from human peripheral blood null cells: evidence for regulation by T-lymphocytes and monocytes

Colony assays in methylcellulose of primitive erythroid precursors (BFU-E) were carried out from the null cell fraction of normal human peripheral blood lymphoid cells. There was little proliferation or maturation of BFU-E as assessed by both the number and the size of colonies formed, when null cells alone were cultured. Culture of null cells with up to 8 X 10(5) autologous T-lymphocytes per ml led to considerable stimulation of colony growth and maturation. Culture of null cells with peripheral blood monocytes also resulted in the indication of BFU-E growth, although the response was inferior to the seen with T-cells. Co-culture of null cells together with both T-cells and monocytes resulted in a uniformly greater response than with either alone, and this was shown to be due to a positive interaction between these two cell types.

Production of the complement cleavage product, C3a, by activated macrophages and its tumorolytic effects

Mouse peritoneal macrophages were activated in serum-free culture with lipopolysaccharide, dextran sulphate or C3b. They were found to liberate into the culture medium a cytolytic factor and a factor which was pharmacologically indistinguishable from C3a. The cytolytic activity was neutralized by antiserum against C3a. These results suggest that macrophages can be activated by C3b (or agents that generate C3b) to cleave C3, which they themselves produce. In this way the activated macrophages form C3a, which appears to be a major factor in macrophage-mediated cytolysis. These findings have implications in tumour immunity and in the pathogenesis of inflammatory reactions.

Cytolytic effects of the complement cleavage product, C3a

Purified C3a, a cleavage product of the third component of complement,was incubated with various cell types of human and mouse origin. All the tumour cell types tested were lysed by low concentrations of C3a, whereas normal human lymphocytes were relatively resistant. No lysis was produced by C3 or C3b. The possible role of C3a in immunity against tumours is discussed.