Elevated System Energy Expenditure in Sickle Cell Anemia

Abstract

In Sickle-cell Anemia (SCA), anergy (lack of metabolic energy) and elevated resting energy expenditure (REE) are commonly observed phenomena. The many systemic changes in Sickle-cell anemia are, therefore, associated with measurable changes in patterns of energy uptake, utilization and efficiency. Understanding the scientific basis of these structural and energy changes suggest mechanisms of possible amelioration.The structural and energy changes in sickle-cell anemia can be viewed at different levels: at the level of the whole person, as reflected in anergy and elevated resting energy expenditure. At the level of the whole blood tissue, as shown in lowered blood pH (high hydrogen ion, H+, concentration). This is also associated with structural changes in polyhedral charge-packing of hydrogen and hydroxyl ions (octahedral charge-packing, which is the ideal is not achieved). At the specific organ level, this is shown in the elevated energy cost of kidney proton-dialysis. Because of this kidney disease is a major cause of death among sickle cell sufferers. The cellular level shows the disruption of the erythrocyte membrane itself. The anti-turbulence biconcave ‘erythrocytoid’ shape is changed to the sickle-shape, resulting to increased blood flow-turbulence. This overworks the heart; causing high heart disease rates among patients. At the molecular level, this results to, for example, the inability to metabolize the key energy-source molecule glucose. This results to, as well as inability to extract energy from glucose, glycation of hemoglobin. Glycated hemoglobin has poor oxygen-carrying power, compounding the problem of the little hemoglobin available. Also there are shifts in redox equilibriums, enzyme and metabolite concentrations and activities, and so on. All these result to extra-energy costs to try to restore system optimal state of efficiency and stability. All these, together, explain elevated resting energy expenditure in sickle cell disease. Different researchers have, over the years, discovered that sufferers from sickle cell anemia (SCA) expend more energy maintaining the same mass of their bodies than normal people (Kopp-Hollihan et al, 1999; Borrel et al, 1998). Some have worked to establish more efficient measurements of the observed differences from normal (Buchowski et al, 2002). Others have worked on theories and experiments towards remediation (Bourre, 2006; Enwonwu, 1988). On the internet, there are sites actively publicizing high-energy foods they consider ideal for sickle cell sufferers (Sherry, 2011). In folk medicine in the African communities, where sickle anemia is common, easy to digest high-energy foods are usually recommended for sickle cell patients. To appreciate why a sick body, such as that of the sufferers of sickle-cell anemia, would cost more energy to maintain, as reflected in the higher resting energy expenditure (REE), than