ABSTRACT
Background: Immunomodulatory effects of macrolides in chronic inflammation are well known. In this study, we tested our hypothesis that azithromycin (AZT) can decrease inflammation in pediatric patients with sickle cell disease (SCD). Methods: The use of AZT as an anti-inflammatory agent was evaluated in double-blind, placebo-controlled, cross-over study for 8 weeks of treatment with 8 weeks of washout. Blood samples were collected before (PRE) and after (POST) each 8-week treatment period. Repeated measures analysis of variance (ANOVA) with post hoc multiple comparison procedures and Chi-square test were used for statistical analysis of the data. Complete blood count, distribution of the lymphocyte subsets, and plasma levels of markers of vascular damage were analyzed. Results: A significant decrease in the number of leucocytes and granulocytes was observed in AZT group following treatment. An opposite dynamic was observed in placebo group; numbers of granulocytes significantly increased at POST interval. All markers of vascular damage were reduced in AZT group at POST interval with overall significance (P = 0.026). The most prominent significant changes were observed in levels of myeloid-related protein 8/14 (MRP8/14), lipocalin A (NGAL), matrix metalloproteinases (MMP) 9, and insulin-like growth factor-binding protein (IGFBP) 4. Plasma level of C-reactive protein (CRP) was significantly decreased in AZT group as well. Conclusions: Data suggested that AZT may be beneficial in management of microvascular injury in SCD.
ABSTRACT
Vascular cell adhesion molecule-1 (VCAM-1) has been implicated as being important in the pathophysiology of acute pain episodes (APE) and acute chest syndrome (ACS) of sickle cell disease (SCD). The frequency of these episodes is reduced by chronic transfusion therapy. The impact of chronic transfusion therapy on VCAM-1 expression is unknown. Soluble VCAM-1 (sVCAM-1) levels were measured in plasma using an ELISA assay (R&D Systems) in 61 patients with SCD (age range 1.5-20 years) and 12 normal controls (2.5-14 years). SCD patients included 20 with ACS, 14 with APE, 12 at well-child visits, and 15 receiving chronic transfusion therapy. Asymptomatic SCD patients had higher sVCAM-1 levels compared to normal subjects (P < 0.001). Levels of sVCAM-1 were further elevated during ACS (P < 0.001) and APE (P = 0.072) and returned to the asymptomatic range on resolution. Levels were significantly lower in transfused patients (P = 0.003) compared to asymptomatic SCD patients. Our findings of increased VCAM-1 expression during ACS and perhaps APE offer a rationale for therapeutic use of cytokine and other VCAM-1 modulators. The reduction of sVCAM-1 levels observed in our transfused SCD patients offers insight into the mechanism of the protective effect of transfusion against ACS and APE and possibly stroke.
