Sickle Cell Against Malaria

Sickle Cell is a recessive inherited trait caused by a mutation in the hemoglobin-beta gene on chromosome 11. The disease causes red blood cells, to be abnormal (crescent shaped). 

Normal and Sickle red blood cells

An article published by ScienceDirect notes that Sickle human hemoglobin (Hb) can actually protect against malaria. The article notes that people that are heterozygous for the sickle cell gene, show a survival advantage in areas where malaria is prevalent. The disease in fact does not prevent the host from developing the parasite, but makes it tolerant to it. Individuals with sickle cell accumulate cell free hb and heme (non-protein part of hb) in the plasma which induces the expression of heme oxygenase-1. This enzyme catalyzes heme into other molecules including carbon monoxide, which binds to sickle hb and prevents it from releasing more heme and hence the pathogenesis of experimental malaria. 

Specialists think that the mechanism involving sickle hb is similar to other genetic blood diseases that also seem to provide  a type of protection to the host. These findings provide a great advantage and open ways to new therapeutic inventions against malaria.

Sickle-cell Disease Cure May Be on the Horizon

An article from The New York Times discusses that success may have been made in "the first genetic cure of a common genetic disease". Sickle-cell disease affects the blood. It causes red blood cells to have a sickle or crescent shape as opposed to normal cells with a more smooth and circular shape. (NIH) The sickle shape of the cell causes issues with the ability of the cell to move through the circulatory system. It typically affects individuals of African descent. There is one specific gene that causes sickle-cell disease. It was believed that the disease could be cured if they could fix the problem on a genetic level. Stem cells are taken from a patient's bone marrow and then they are genetically modified and put back in to the individuals bloodstream, with hopes that they will form new and healthy blood cells.

I know that sickle-cell disease can be very painful and dangerous. The young man in the article that received the gene therapy treatment had suffered from four strokes by the time he was 18. Many people also die from complications of this disease. The fact that we are capable of making changes to someone on a genetic level is incredible. This could be a huge stepping stone in treatment for many other genetic disorders.

Sickle Cell Trait Has Possible Link to Chronic Kidney Disease Among African Americans

A large multicohort study, conducted by a research team at John Hopkins University in Baltimore, found a possible association between sickle cell trait (SCT) and chronic kidney disease (CKD.) African Americans with a sickle cell trait do not develop sickle cell anemia but instead carry a single copy of the gene that is known to cause the disease. Sickle cell anemia is a disease that is characterized by misshaped red blood cells (sickle cells) that are sticky and stiff leaving the blood vessels more prone to obstruction. In contrast, SCT is less severe where only in very rare cases do people develop deformed red blood cells as a result of severe dehydration.

The researchers noted a gap in knowledge regarding possible conditions influenced by SCT. They highlight that African Americans have a disproportionately higher risk of developing chronic kidney disease and progression to end-stage renal disease (ERD.)  “SCT may be an important and unrecognized risk factor for renal disease in this population.” The study analyzed 5 US population based studies involving 2,233 African American participants 1,248 of which has SCT. 2,233 individuals had CKD, with 19.2% of individuals with SCT and 13.5 without the condition.

These findings imply that there is a higher risk for developing CKD in African Americans with SCT. In addition, researchers found that individuals with SCT have a faster decline in the rate at which fluids are filtered through the kidney. Further, 31.8% of people with SCT experienced albuminuria, a sign of a kidney disorder characterized by excessive protein in urine.

This study suggests the need for more research on kidney disease and other renal complications. Kidney failure is the 8th leading cause of deaths in the US. 90% of people with stage 3 CKD are unaware (Kidney Fund.Org, 2012.) This article is specifically significant to me because I have family members who have complications with their kidneys and who are on dialysis. If there is a better way to detect possible links between genes and the development of kidney disease perhaps possible interventions and medications can decrease the number of people affected in this vulnerable population.  

 Article: http://www.medicalnewstoday.com/articles/285322.php

Additional Link: Kidney Fund. Org. (2012, August 12). Kidney Disease Statistics. Retrieved from http://www.kidneyfund.org/about-us/assets/pdfs/akf-kidneydiseasestatistics-2012.pdf