Abstract:
Abstract: Sickle cell disease (SCD) is an inherited blood disorder that can result in vasculopathy
and end organ damage. Angiogenesis has been implicated as a key contributing factor to vascular
mediated tissue injury in SCD. The relative plasma levels of angiopoietin-1 (Ang-1), angiopoietin-2
(Ang-2), and vascular endothelial growth factor (VEGF) greatly influence angiogenesis. Dysregulation
of these growth factors, leading to a pro-angiogenic state in SCD patients, has been documented in
the developed world but there is very little data in Africa. There is the need, therefore, for studies
in Ghanaian SCD patients. The aim of this study was to assess plasma levels of Ang-1, Ang-2, and
VEGF in homozygous (HbSS) SCD patients with or without complications and healthy controls
(HbAA) in Ghana. The study was a case-control study involving 544 participants: 396 HbSS SCD
patients and 148 HbAA healthy controls. The study was conducted at the Center for Clinical Genetics
(Sickle Cell Clinic) and Accra Area Blood Centre for National Blood transfusion at the Korle-Bu
Teaching Hospital, Accra, Ghana. The plasma levels of Ang-1, Ang-2, and VEGF of study participants
were measured with a double sandwich enzyme-linked immunosorbent assay (ELISA) technique.
Complete blood count (CBC) was measured with an autoanalyser. The mean plasma Ang-1, Ang-2,
and VEGF were significantly higher in HbSS SCD patients with or without complications than healthy
controls (p < 0.001). The Ang-2/Ang-1 ratio was significantly lower in the controls than the HbSS
patients (p < 0.001). The Ang-2/Ang-1 ratio was higher in the HbSS patients with leg ulcers as
compared with patients with other complications and healthy controls (p < 0.001). There were higher
leucocyte counts in HbSS patients than healthy controls. Overall, there was elevated plasma levels of
Ang-1, Ang-2, and VEGF in SCD patients. The higher Ang-2/Ang-1 plasma levels in patients with
leg ulcers suggests a possible ongoing angiogenesis and response to inflammatory stimuli. The study
provides a first report on plasma levels of angiopoietin-1, angiopoietin-2, and vascular endothelial
growth factors in homozygous sickle cell disease patients in Ghana.
