Thrombospondin-1 (TSP-1) and 25-hydroxyvitamin D (25-OHD) play significant roles in the pathogenesis of sickle cell anemia (SCA). TSP-1 enhances cellular adhesion/inflammation, hence contributing to vaso-occlusive crisis (VOC); vitamin D, in contrast, retards inflammation and may lower rate of pain episodes. We determined serum levels of TSP-1 and 25-OHD in Nigerian children with SCA and their matched hemoglobin AA controls; and assess the relationship between the 2 biomarkers.
In total 90 children (32 SCA in steady state, 30 SCA in VOC, and 28 HbAA controls) were studied. Serum TSP-1 and 25-OHD levels were measured with ELISA and HPLC, respectively.
The mean TSP-1 of children with VOC was significantly higher than those in steady state (P=0.022) and HbAA controls (P<0.001). Similarly, the mean TSP-1 of those in steady state was higher than the controls (P=0.007). However, mean serum 25-OHD of the children with VOC was significantly lower than those in steady state (28.9±8.2 ng/mL vs. 37.1±12.3 ng/mL, P =0.004). There was a significant inverse correlation between TSP-1 and 25-OHD among the VOC subgroup, r=−0.57, P=0.001. The mean TSP-1 of the 28 children with SCA who had suboptimal vitamin D (213.5±118.6 ng/mL) was higher than 144.2±58.7 ng/mL of the 34 SCA who had normal serum vitamin D, P=0.008.
Children with SCA, especially those with VOC, had high serum TSP-1 and low 25-OHD. Also, an inverse relationship exist between serum 25-OHD and TSP-1 in children with VOC. These findings provide basis for further studies into the regulation of TSP-1 by vitamin D.
*Department of Pediatrics and Child Health, Obafemi Awolowo University (OAU)
Departments of ‡Chemical Pathology
†Pediatrics, OAU Teaching Hospitals Complex, Ile-Ife, Nigeria
§Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait
S.A.A. and O.S.S.: study conception and design. S.A.A., O.S.S., and A.D.A.: data acquisition, analysis and interpretation of data. S.A.A.: initial drafting of the article. S.A.A., O.S.S., and A.D.A.: critical revision for important intellectual content and final approval. S.A.A. and A.D.A.: guarantor of the article.
The authors declare no conflict of interest.
Reprints: Samuel A. Adegoke, MBChB, FWACP, MD, MPH, PhD, Department of Pediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Nigeria, P.M.B. 003, Ile-Ife, Nigeria (e-mail: email@example.com).
Received April 10, 2018
Accepted October 30, 2018