Short summary

Diabetes is a frequently occurring disease, associated with a significantly high mortality rate, which to a to a large extent, is dependent on an increased occurrence of atherosclerosis that produce vascular diseases. Evidence shows that development of aterosclerosis is affected by vitamin K intake and is reflected in the level of vitamin K dependent proteins, which is an indirect measure of vitamin K status. Meanwhile no studies ,that directly determine vitamin K status in diabetics and highlights the possible association between serum vitamin K status and aterosclerotic disease, exists. 

Rationale

Diabetes is a common disease (about 320.600 danish diabetics, 2012) that causes significant excess mortality, due to a number of serious late complications of diabetes, among other things cardiovascular diseases. The reasons to this can be calcification of the vascular system, which can lead to development of among other things hypertension, myocardial ischaemia and heart failure. Evidence shows that development of artheriosclerosis (intimal calcifikation) is affected by vitamin K-intake, and vitamin-K-deficiency has been found to increase the risk for developing cardiovascular disease.

Today the vitamin-K-level is most often measured indirect by measuring biomarkers in plasma. We wish to develop a mass spectrometric method to measure vitamin K directly, whereby the sensitivity is increased. Afterwards the method is applied on a diabetes population to investigate whether vitamin-K-deficiency is associared with late complications of diabetes.

From 2007-2010 a diabetes biobank was built at Vejle Hospital, SLB. It contains blood samples from randomly chosen citizens from the earlier Vejle Amt (age 25-75, with (n=3,392) and without (n=5,115) diabetes). The laboratory on the hospital has long experience with mass spectrometry (over 10 years) and is equipped with high-sensitive tandem mass spectrometers. We expect that the optimization of the purification and the chromatography gives a better sensitivity than has earlier been seen.

We are interested in vitamin K1 (found in foods), MK-4 (produced in the body), and MK-7 (produced by the intestinal flora). Moreover these tree vitamin K's are the ones used as food supplements.   

The project consists of a laboratory-part and a hypothesis-generating-part.

The objective of Part 1 of the project is to:

• Develop a sensitive mass spectrometric method for quantification of vitamin K1, MK-4 and MK-7 in serum.
• Establish reference intervals for vitamin K1, MK-4 and MK-7 in serum of healthy people.

The objective of Part 2 of the project is to:

• Examine if there is an association between the concentration of vitamin K1, MK-4 and MK-7 in serum and occurrence of micro- and macrovascular late complications of diabetes.
• Examine the correlation between the concentration of vitamin K1, MK-4 and MK-7 in serum and dp-ucMGP (a vitamin K-dependent protein).

Description of the cohort

The biological material in Vejle Diabetes Biobank consist of fasting blood samples and urin from 3.392 citizens with and 5.115 without diabetes in total.

In the project it is investigated, whether there is a difference in vitamin K-concentration between different groups of non-diabetics and diabetics with/without late complications of diabetes. This is done by dividing the participants into the following 5 groups on the basis of their T2DM-status at the time of inclusion as well as register data:

Grp. 1) Non-diabetics

Grp. 2) T2DM, no micro- or macroangiopathic disease

Grp. 3) T2DM, retinopathy and/or nephropathy, no macroangiopathic disease

Grp. 4) T2DM, ischemic heart disease and/or peripheral vascular disease, no microangiopathic disease

Grp. 5) T2DM, micro-(retinopathy, nephropathy) and macroangiopathic disease (ischemic heart disease, peripheral vascular disease)

Grp. 3-5 is selected on the basis of the above-mentioned diagnosis from register data. All the persons in Vejle Diabetes Biobank with the individual diagnosis are included. 

Data and biological material

We will measure vitamin K status on the blood samples from Vejle Diabetes Biobank.

The registerdata will be collected from the following registers: The Danish National Patient Register (Landspatientregisteret (LPR)), The National Health Insurance Service Register (Sygesikringsregisteret), The Register of Medicinal Product Statistics (Lægemiddelstatistikregisteret) and The Danish Civil Registration System (CPR-registret).

Collaborating researchers and departments

The project is a PhD-project:

Department of Clinical Immunology and Biochemistry (KIBA), Vejle Hospital

• PhD student, cand.scient medicinal chemistry, Ida Bøgh Andersen
• Consultant and Associate Professor Jonna Skov Madsen, PhD
• Consultant Claus Lohman Brasen, PhD
• Biochemist Anne Vibeke Schmedes, PhD

Medical department, Kolding Hospital

• Chief physician, clinical lecturer, Ph.D. Ole Winther Rasmussen

• Professor Anders Green, DMSc