Sickle Cell Anemia Clinical Trial
Official title:
The Effect of Jobelyn ( Extract of Sorghum Bicolor) on the Haematological Parameters of Patients With Sickle Cell Anaemia Disease.
The primary objective is to determine if there is a significant increase in the haematocrit value of patients on Jobelyn and standard therapy compared to those on standard therapy alone.
Sickle cell anaemia is an inherited haemoglobinopathy caused by a point missense mutation
(GAG to GTG) in the beta globin gene that resulted in the substitution of an acidic amino
acid ( glutamic acid) with a neutral and hydrophobic amino acid (valine) in the codon 6 of
the beta globin chain. This genetic defect has a prevalence of 20% to 40% in Sub Saharan
Africa, 7.8% in African Americans and to a lesser extent in the Middle East, Mediterranean
and India.
The higher frequency in the sub Saharan Africa is thought to be due to the selective
advantage the gene confers on the traits (heterozygotes state) in malaria zone. Nigeria is
the most populous country in this region with about 24% frequency of the mutant gene. The
prevalence of sickle cell anaemia in Nigeria is about 20 per 1000 life births. This implies
that Nigeria may have the highest burden of the disease in the world.
The severity of sickle cell disease varies. The disease is more severe in patients with
haemoglobin SS or haemoglobin S beta thalassaemia than in those with haemoglobin S beta+
thalassaemia or haemoglobin SC disease. The Arab - Indian haplotype produces a less severe
disease than the African haplotype. Similarly, the coinheritance of one or two, alpha globin
chain deletions or high fetal haemoglobin level in hereditary persistence of fetal
haemoglobin are associated with mild disease, The severity is therefore higher in the Sub
Saharan African sub region. However, the severity of the disease varies widely for
unexplained reasons among patients with haemoglobin SS in this region.
The beta S globin chain binds at the valine site with complementary hydrophobic effects on
other beta globin chain. This triggers the formation of polymers of haemoglobin. The rate of
polymerization is increased with increase in intracellular deoxy-haemoglobin. Factors that
promote polymerisation are dehydration, acidosis, increase in the level of 2,3
diphosphoglycerate which may occur in infections. On the other hand, the association of
haemoglobin 5 with other haemoglobin that have higher oxygen affinity-like haemoglobin F or
haemoglobin A reduce the rate of polymerisation.
The haemoglobin polymer forms a firm gel that damages the cellular membrane. The damaged
membrane causes movement of potassium and water out of the cell thus leading to dehydration
and more polymer formation. This damage also causes the negatively charged
phosphatidylserine to move to the membrane surface and the red cell becomes deformed in
shape, more rigid and more adherent to the vascular endothelium. The result of these are
easy fragmentation of the membrane and extra vascular haemolysis, complement mediated lysis
of the cell and intravascular haemolysis, shortened red cell survival to 4 to 25 days,
trapping of rigid irreversible sickle cells in the post capillary venules which is promoted
by leukocytosis, platelet activation and inflammatory cytokines.
The release of intravascular haemoglobin mobs up nitric acid which has a vasodilatation
effect. This aggravates the already deficient tissue perfusion. A vicious circle is formed
that eventually leads to tissue hypoxia, sequestration of blood in organs with sinuses
(spleen, liver, lungs and the penis). There is also a chronic haemolytic anaemia with
insufficient increase in the production of erythropoietin due to the fact that the beta S
globin chain has a lower affinity for oxygen and therefore releases oxygen easily to the
tissue. To further reduce erythropoiesis is the increase of inflammatory cytokines that
inhibit haemopoiesis i.e interleukin 1 and tumor necrotic factor. On the other hand an
increase in the red cell mass tends to increase vascular occlusion and ischemic crises. The
ideal stable haematocrit for sickle cell disease is therefore between 24% and 28%. At this
range of haematocrit, tissue hypoxia is minimized and painful crises are easier to control.
Factors that precipitate crises are dehydration, infection, extreme heat or cold and
physical or emotional stress. These factors are prevalent in our environment. Early
detection and preventive measures are very important in the management of sickle cell
disease. To enhance red cell production, patients are offered regular folic acid. To prevent
malaria, prophylactic paludrine is given and infection is treated with appropriate
antibiotic. Among the anti sickling drugs, hydroxyurea, an inhibitor of ribonucleotide
reductase, has been shown to decrease the rate of painful crises probably by reducing
adhesion to the endothelium, increasing the proportion of fetal haemoglobin within the cell
and reduction in the white blood cells and platelets. Other drugs on trial are butyrate
compounds and analogues of azacytidine.
Other modalities are blood transfusion, exchange blood transfusion, stem cell transplant and
the possibility of gene therapy is realistic. These modalities are not without their side
effects and high costs. A new drug added to the routine drugs might minimize tissue.
Hypoxia, rate of sickling and haemolysis if the haematocrit is within the steady state
range, white cells count are reduced and inflammatory cytokines are reduced.
Available reports suggest that sickle cell erythrocytes are susceptible, to endogenous free
radical mediated oxidative damage as indicated by marked increase in lipid peroxidation and
superoxide dismutase level in haemoglobin SS patient. However there remain discrepancies in
the status of anti oxidant enzymes and vitamins in the patients.
Sorghum bicolor, a grain long used in Africa for its high nutritional value also exhibits
strong antioxidant properties and antiinflammatory effects. The traditional preparation of
Sorghum bicolor has an oxygen radical absorbance capacity (ORAC) OF 3,123 micro mole TE/g.
This is much higher than other botanical preparations. Complementing the antioxidant
properties, sorghum bicolor also exhibits anti inflammatory effects and demonstrated
selective COX-2 inhibition, providing effective reduction in inflammation without residual
side effects.
Sorghum bicolor extract has been shown to increase the haematocrit and haemoglobin level and
reduce the white cell count in trypanosome brucei brucei induced anaemia in experimental
rabbits. These effects were conclusive within 49 days of experimentation. Animals sacrificed
after the administration of lethal dose Jobelyn were shown to have congestion of the liver,
kidneys and lungs. This might be as a result of direct effect on these organs or a sign of
cardiotoxicity. However there is a wide therapeutic range.
Jobelyn is the proprietary name for the product intended to treat sickle cell disease and it
is currently marketed as a nutritional supplement. Jobelyn is marketed in 250mg capsules of
Sorghum bicolor leaf extract. The product is widely marketed in many countries including
Nigeria. Many of our sickle cell patients have been using it regularly for a long time
without any report of adverse effect.
The sorghum bicolor extract is expected to increase the haematocrit of' sickle cell anaemia
within a short time, to reduce leukocytosis during sickling and therefore reduce vascular
occlusion and improve tissue perfusion. The selective effect on COX 2 and the moderation of
inflammatory cytokines is expected to reduce painful crises and inhibition of haemopoiesis.
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Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Single Blind (Caregiver), Primary Purpose: Treatment
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