Two Israeli research teams have separately become the first to discover two
different benefits from vitamin D against common liver diseases – hepatitis C
and cirrhosis.
One involved the mechanism in human cells in the lab,
while and the other proved itself on liver tissue in rats. The two discoveries
have not yet been tested clinically.
Prof. Ran Tur-Kaspa, from the Rabin
Medical Center- Beilinson Campus, and his team worked on hepatitis C, the major
factor in chronic liver disease that can lead to cirrhosis. It is also the main
cause in the Western world of organ failure requiring a liver transplant and is
one of the causes of primary liver cancer.
Antiviral treatment can help
in half the cases, but the side effects are serious even if the treatment is
effective.
Tur-Kaspa, a liver specialist and researcher who is dean of
the Galilee Medical Faculty in Safed, said there is a constant search for
medications and other technologies that are more effective and accompanied by
fewer side effects.
He and his team investigated ordinary vitamin D,
which is already taken by many people as prevention for numerous diseases, to
see whether it had any effect on hepatitis C and on liver cells that host it.
They discovered, and published in Hepatology, a peer-reviewed medical journal,
that vitamin D directly halts the activity of viruses in general and hepatitis C
in particular. They also found that a system for actively producing vitamin D is
found in liver cells and can activate the immune system and repress the
virus.
The research showed without doubt that vitamin D functions in the
liver cell, and it causes an increase in naturally produced interferon and
repression of the production of the virus, said Dr.
Romy Zemel, who was
part of the team. The research proves that integrating the use of interferon and
vitamin D boosts the effects synergistically, beyond the effects of each
alone.
Interferons are a family of naturally occurring proteins that are
made and secreted by immune-system cells. Thus, with the right combination, said
the Beilinson researchers, one could destroy the virus. Their discovery was made
serendipitously.
Vitamin D is produced as a result of exposure to the sun
or taken in the diet or by supplements.
Its classic role, said Tur-Kaspa,
is to protect the balance of calcium and phosphorus in the body. Over the years,
additional influences such as on the immune system became clear, and at the same
time, vitamin D became popular as a number of health benefits were
reported.
The Beilinson discovery of the weakening of the hepatitis C
virus in the presence of the vitamin opens up a potential treatment for the
infections, so one can improve the efficacy of treatment while reducing the
dosage of interferon, said Tur- Kaspa.
Meanwhile, the latest issue of Tel
Aviv Sourasky Medical Center’s newsletter published an article by Prof. Shimon
Reif and colleagues on how vitamin D fights liver cirrhosis, in which liver
tissue is replaced by fibrotic scar tissue, usually collagen, leading to the
loss of liver function.
Special cells in the liver called hepatic
stellate cells (HSCs) collect vitamin D when they are “resting.”
After
they are activated, they produce collagen, which leads to fibrosis. Using liver
tissue taking from rodents, the Sourasky team treated them with vitamin D and
increased the expression of a receptor for the vitamin. This significantly
repressed the growth of HSCs, they found.
The same effect was then found
in live rats.