Pseudoxanthoma Elasticum:
Are Vitamin K, Its Precursors and Metabolites
the New Kids on the Block?

By Berthold Struk, MD, PhD

Evidence from ABCC6 (-/-)

Mice Tissue calcification in PXE results from loss of function of ABCC6 in the liver
The phenotype can be rescued by transplantation of normal liver cells (from wild type mice) into the knockout mouse

Metabolic Disease Hypothesis

Tissue calcification is due to the absence of a plasma factor secreted from the basolateral hepatocyte membrane due to loss of function of ABCC6
The missing plasma factor could be vitamin K, a vitamin K precursor or a vitamin K metabolite
- since vitamin K is an important co-factor for the gamma-carboxylation of gla-proteins, that in the carboxylated form prevent tissue calcification.

GLA-Proteins

Prevent tissue calcification
- if they are carboxylated
GLA-proteins are the
- Vitamin K-dependent clotting factors II, VII, IX and X (liver
- osteocalcin
- matrix gla-protein (MGP)

Matrix GLA Proteins

History of K-Vitamins

The chemical substance class of "quinones"
- was known since at least 1910
- their ability to oxidize iodide to iodine
- iodometric determination
Iodometric determination
- was used for the determination of the content of quinones in different
  - animal tissues
  - foods
Iodometric determination
quinone + hydriodic acid → reduced quinone + iodine
I2 (Iodine) + Starch Blue Color
1945 Weston Price described a new vitamin-like activator
- influential on utilizing minerals
- protecting against tooth decay
- protecting against heart disease
- important for growth, development, reproduction and function of the brain

Chemical Structure of Vitamin K Precursors and Metabolites

Vitamin K dependent carboxylation of GLA-proteins

the Vitamin K-dependent gamma-glutamyl carboxylase (GGCX)
- rearranges the chemical bonds within carbon dioxide by creating a carboxyl group
- adds such carboxyl group as second group to the side chain of the amino acid glutamate and transforms it into ccarboxyglutamate
the process is called c—carboxylation

Natural Sources of K Vitamins

Vitamin K2 Content of Selected Foods
(micrograms per 100 gram serving)

What is Natto?

Nattō (なっとう or 納豆?) is a traditional Japanese food made from fermented soybeans, popular especially for breakfast
As a rich source of protein, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan
For some, nattō can be an acquired taste due to its powerful smell, strong flavor and sticky consistency
In Japan nattō is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido .
Nattō is made from soybeans, typically a special type called nattō soybeans.
- Smaller beans are preferred, as the fermentation process will be able to reach the center of the bean more easily.
- The beans are washed and soaked in water for 12 to 20 hours. This increases the size of the beans.
- Next, the soybeans are steamed for 6 hours, although a pressure cooker can be used to reduce the time.
- The beans are mixed with the bacterium Bacillus subtilis natto, known as nattō-kin in Japanese.
- From this point on, care has to be taken to keep the ingredients away from impurities and other bacteria.
- The mixture is fermented at 40°C for up to 24 hours. Afterwards the nattō is cooled, then aged in a refrigerator for up to one week to add stringiness. During the aging process at a temperature of about 0°C, the Bacilli develop spores, and enzymatic peptidases break down the soybean protein into its constituent amino acids.

Vitamin K2 Supplements
(ASK YOUR PHYSICIAN FIRST!)

Editor’s Note – Dr. Struk urges NAPE readers to tap into and read more about Vitamin K at the following website which provides much useful detail:
http://www.westonaprice.org/basicnutrition/vitamin-k2