Heme changes HIF-α, eNOS and nitrite production in HUVECs after simvastatin, HU, and ascorbic acid therapies.

The sickle cell disease (SCD) is a hemolytic genetic anemia characterized by free heme and hemoglobin release into intravascular spaces, with endothelial activation. Heme is a proinflammatory molecule able to directly activate vascular endothelium, thus, endothelial dysfunction and vascular disease are major chronic events described in SCD. The aim of this study was to evaluate the production of endothelial nitric oxide synthase (eNOS), nitrite and hypoxia inducible factor alpha (HIF-α) in HUVECs (human umbilical vein endothelial cells) activated by heme in response to simvastatin, hydroxyurea (HU), and ascorbic acid therapies. eNOS and HIF-α production were evaluated by ELISA and nitrite was measured by the Griess technique. The production of HIF-α increased when the cells were stimulated by heme (p<0.01), while treatment with HU and simvastatin reduced the production (p<0.01), and treatment with ascorbic acid increased HIF-1a production by the cells (p<0.01). Heme increased eNOS production, (p<0.01) but showed a heterogeneous pattern, and the lowest concentrations of all the treatments reduced the enzyme production (p<0.01). The nitrite production by HUVECs was enhanced by stimulation with heme (p<0.001) and was reduced by treatment with HU (p<0.001), ascorbic acid (p<0.001) and simvastatin (p<0.01). In summary, our results suggest that the hemolytic vascular microenvironment in SCD requires different therapeutic approaches to promote clinical improvement, and that a combination of therapies may be a viable strategy for treating patients.

Nasopharyngeal and Oropharyngeal Colonization by Staphylococcus aureus and Streptococcus pneumoniae and Prognostic Markers in Children with Sickle Cell Disease from the Northeast of Brazil.

We investigated the nasopharynx and oropharynx microbiota in sickle cell disease (SCD) to identify the microorganisms, antibiotic sensitivity, prevalent serotypes, and association of with laboratorial markers. Oropharynx/nasopharynx secretions were investigated in 143 SCD children aging 6 months to 17 years. Pathogens were isolated using standard procedures, and laboratorial markers were performed by automated methods. Staphylococcus aureus (S. aureus) was isolated from nasopharynx and oropharynx of 64 and of 17 SCD children respectively. Streptococcus pneumoniae (S. pneumoniae) was isolated from the nasopharynx and oropharynx of eight SCD patients. Serotypes of S. pneumoniae were 19F, 23F, and 14. All isolates were susceptible to penicillin, and patients whose nasopharynx and oropharynx were colonized by S. pneumoniae had high concentrations of aspartate transaminase, alanine transaminase, and ferritin. S. pneumoniae isolated were not penicillin-resistant serotypes suggesting that the use of penicillin for prophylaxis and/or treatment of infections is safe. Our finding of colonization and laboratory evaluation in SCD patients suggests that microorganisms are involved in the modulation of chronic inflammatory. The association of colonized microorganisms and laboratorial markers suggest a new approach to these patients follow-up, and additional studies of microorganism colonization and their association with SCD patients' clinical outcome will improve control and prevention strategies.

Association of homocysteine and inflammatory-related molecules in sickle cell anemia.

OBJECTIVE: Investigate the role of homocysteine (Hcy), Th17-related cytokines, and adhesion molecules in the inflammatory state seen in the sickle cell anemia (SCA). METHODS: We studied the Hcy, interleukin (IL)-17, and transforming growth factor ß (TGF-ß) cytokine levels of 62 SCA patients, as well as the expression levels of inflammatory and endothelial activation markers. RESULTS: We found significant associations between Hcy levels and increased expression of IL-17 and TGF-ß among SCA patients, and a positive significant correlation between Hcy and soluble vascular cellular adhesion molecules (sVCAM). SCA individuals had raised IL-17 levels when compared with controls. DISCUSSION: These results suggest a possible role of Hyc in the induction of TGF-ß and IL-17. Other authors proposed that Hcy may contribute to the initiation and progression of vascular disease by monocyte activation, resulting in the secretion of cytokines that amplify the inflammatory response. The role of Hcy in cytokine production and oxidative stress in the endothelium may explain the increase of sVCAM expression and, the vascular activation currently described among the SCA individuals with the highest Hcy serum levels. The chronic inflammation was observed in hyperhomocysteinemic mice, with an increased expression of VCAM-1 and plasma levels of tumor necrosis factor-alpha, showing an association of this inflammatory molecule and vascular changes. CONCLUSION: Our findings suggest that the increased levels of IL-17,Hcy and sVCAM contributes contributes to the vascular inflammation and activation presented by SCA patients, which probably have an important role in vaso-occlusion. On the basis of the presented data, IL-17 and Hcy might be considered as important components in the pathogenesis of SCA.