What is Sickling?
Sickling is when the hemoglobin inside red blood cells sticks or clumps together, causing the cell to become fragile, rigid, and crescent—or sickle—shaped. Take a closer look at how red blood cells become distorted as well as how these sickled cells can affect your body and cause the symptoms and complications of sickle cell.
What Causes Sickling?
Each red blood cell is densely packed with hemoglobin proteins. Healthy red blood cells are packed with a form of hemoglobin called normal adult hemoglobin (HbA). HbA looks and functions properly all the time.
In sickle cell, red blood cells are packed with hemoglobin sickle (HbS) proteins. HbS proteins are created due to having two copies of an abnormal HBB gene. These proteins look and work normally in a high-oxygen state (when carrying oxygen to your cells and organs), but they can change to an abnormal shape when they are in low-oxygen state.
This change in shape (called a conformational change) can cause these HbS molecules to stick to one another. When there are many HbS molecules in a cell, they clump together and form long chains called polymers in a process called polymerization.
The amount of HbS molecules you have compared with other forms of hemoglobin in the cell—and their subsequent polymerization—are the ultimate cause of sickling in red blood cells as well as the associated symptoms and complications of sickle cell.
Check out the video to see how sickle cell occurs and uncover how sickling can cause silent, progressive damage to the body.
Consequences of Sickling
Sickled red blood cells are very rigid and sticky and can have difficulty moving through small blood vessels. They can slow or block blood flow in these blood vessels (known as vaso-occlusion), preventing oxygen from properly circulating in the body as pictured in the image below. Blockages and broken down red blood cells also cause damage to blood vessels (known as vasculopathy), as well as the cells that line them (known as endothelial cells). Additionally, sickled red blood cells are fragile and can break down prematurely (known as hemolysis), lasting only 10 to 20 days throughout the body, compared to 90 to 120 days for healthy red blood cells. This shorter lifespan can create a shortage of red blood cells throughout the body, leading to complications such as anemia and fatigue.
Blockages can lead to unpredictable complications like pain crises or stroke. Repeated blockages, damage to the blood vessels, and hemolysis over time can lead to progressive chronic complications, including organ damage and even organ failure.