Cutting Out Sickle Cells

What am I looking at?

This is an image of human red blood cells. The cells at the bottom of the image display the normal rounded shape of a red blood cell (1). The abnormal cell at the top of the image is a sickle cell (2) – so named because it’s shaped like a curved tool called a sickle that’s used to cut grain or prune bushes.

Biology in the background

Sickle cell disease (SCD) is a group of inherited blood disorders resulting from a mutation in the hemoglobin protein in red blood cells. This mutation changes the shape of the blood cells from round, flexible discs to more rigid, crescent-shaped “sickles.” The change in the shape and rigidity of the blood cells causes an increase in vascular blockages, which can be very painful, debilitating, and dangerous. In addition, these sickle-shaped cells do not live as long as normal blood cells, so people with SCD experience a constant shortage of red blood cells.

Sickle cell diseases affect over 100,000 people in the United States and about 20 million people globally. They are most common in, but not limited to, people of African, Middle Eastern, or Mediterranean descent. In 2023, the United States Food and Drug Administration approved the first genetic treatment for SCD. Instead of addressing just the symptoms of the disease, as previous treatments have, this genetic therapy targets the mutation in the cells’ DNA, addressing the problem at its root.

A normal human red blood cell is about 7 micrometers across, or roughly 15 times smaller than the width of a human hair, whereas a sickle cell is typically from 10 to 15 micrometers long, or roughly seven to 10 times smaller than the width of a human hair.

Technique

This image was created using colored scanning electron microscopy.