Science_Illustrated_Australia_-_Issue70_2019

would suffer the major risk of invasion
by lethal infections. Doctors also use adreno-
cortical hormone, which curbs the infection
caused where the immune system has at-
tacked the body. However, the medication
can neither cure sclerosis nor slow down the
ongoing injury to the nervous system. And
on some patients, the medication has almost
no effect. So it is vital to the world’s 2.3 mil-
lion sclerosis patients that a new and more
efficient treatment be developed.

Attacks on vital nerve cells
Specifically, multiple sclerosis develops
when the body’s immune cells attack particu-
lar high-fat auxiliary cells in the central
nervous system known as oligodendrocytes.
These high-fat cells produce myelin sheaths
around the nerve cell’s fibre threads, like

Immune cells break down the brain

Holes in the brain’s defence mean that confused immune cells

can enter brain tissue and attack the nerve cells’ insulation.

Immune cells destroy insulation

2

Once the blood-brain barrier has been broken down, the

confused immune cells can pass from the blood stream

into the brain. There they liberate more infectious

agents, which destroy the auxiliary cells and oligodendrocytes,

and hence also the insulation around the nerve cell’s end.

Infection breaks down defence

1

The immune system’s cells cause infection in a blood vessel

in the brain by liberating cytokines, which are toxic to

cells. The infection breaks down the blood-brain barrier,

the important semi-permeable border between the brain’s blood

vessels and tissues, which normally keeps out bacteria and viruses.

Several different stem-cell treatments, including

blood stem cells, have already been tested

successfully on sclerosis patients.

SPL

Cytokines

Oligodendrocyte

Myelin sheath

Blood vessel

Immune cell

Blood Cytokines

Ion channel

Blood-brain

barrier

KEN IKEDA MADSEN/SHUTTERSTOCK

58 | SCIENCE ILLUSTRATED

MEDICINE SCLEROSIS