Vitamin B12 and folate metabolism: their role in the regulation of the lipid status

Transcription

1 Vitamin B12 and folate metabolism: their role in the regulation of the lipid status Dr. Attila Bezzegh Semmelweis Medical University, Instutute for Laboratory Medicine, Budapest, Hungary 2017

2 Vitamin B12 Thomas Addison

3 Vitamin B12 = Tetrapyrollic corin ring + Cobalt

4 Vitamin B12 Co HAEM Fe CHLOROPHYLL Mg

5 Vitamin B12 Tetrapyrollic corin ring + Cobalt + R Hydroxy- Methyl- Adenosyl- Cyano-

6 Vitamin B12 Hydroxy- Methyl- Adenosyl- Cyano-

7 Vitamin B12 Hydroxy- Methyl- Adenosyl- Cyano- Bioactive forms of in cells.

8 Vitamin B12 Hydroxy- Methyl- Adenosyl- Cyano- cofactor of methionine synthase enzyme (homocystein pathway)

9 Vitamin B12 Main source: Animal food: meat, meat-offal (liver, spleen, etc.), blood... Milk and dairy products 50% lost during cooking, pasteurization modern agriculture less B12 content Eggs Accessory (not enough): Plants, algaes, bacteria and fungi (yoghurt...) Vegetarian diet!

10 Vitamin B12 Absorption: Protein-binded B12 (with foodstuff proteins) Gastric epithelial cells: HCl secretion + pepsin Parietal cells: Intrinsic Factor (IF) secretion Cobalamin+IF complex Terminal ileum: receptor mediated endocytosis into the enterocyte Degradation of the Cobalamin-IF complex (peroxysome)

11 Vitamin B12 Transportation: Cobalamin + trans-cobalamin II carrier = holotranscobalamin II (HTC II) HTC II = 5-20% of total B12 in the blood (Biologically active cobalamin!) Cobalamin + haptocorrin (trans-cobalamin III) = bounded cobalamin Bounded cobalamin = 80-95% of total B12 in the blood (Inactive molecules)

12 Vitamin B12 Folate Holo-TC (active B12) Methylmalonic acid (MMA) Tetrahydro-folate (THF) Methyl-cobalamin (MB12) Methyonin -synthase B12 Adenosyl-cobalamin (AB12) Methyonin B12 S-Adenosyl-Methyonin (SAM) Methylmalonyl-Co A Sukcinyl-Co A R Mitochondrium Catecholamines, DNA, phospholipids, myelin, polysaccharides, etc. Methy-THF S-Adenosyl-Homocystein (SAH) Homocystein Homocystein (HCY) R-CH 3

13 Assessment and diagnostic markers for B12 / Folate metabolism Serum B12 measurement (Total B12) - no connection to bioactivity Serum Holotranscobalamin (Active B12, HTC) bioactive molecule Serum folate Erythrocyte folate content Blood picture (MCV, MCHC, Hgb, Htc, distribution curves) Serum homocystein (HCy) level Serum / urine Methyl-malonic acid level (not routine test) Total cholesterol (reflective to HCy)

14 Assessment and diagnostic markers for B12 / Folate metabolism Serum B12 measurement (Total B12) - no connection to bioactivity Serum Holotranscobalamin (Active B12, HTC) bioactive molecule Serum folate Erythrocyte folate content Blood picture (MCV, MCHC, Hgb, Htc, distribution curves) Serum homocystein (HCy) level Serum / urine Methyl-malonic acid level (not routine test) Total cholesterol (reflective to HCy)

15 Assessment and diagnostic markers for B12 / Folate metabolism Serum B12 measurement (Total B12) - no connection to bioactivity Serum Holotranscobalamin (Active B12, HTC) bioactive molecule Serum folate Erythrocyte folate content Blood picture (MCV, MCHC, Hgb, Htc, distribution curves) Serum homocystein (HCy) level Serum / urine Methyl-malonic acid level (not routine test) Total cholesterol (reflective to HCy)

16 Vitamin B12 deficiency pathobiochemistry Blocking the folate cycle (methyl- THF THF process stops) Nucleic acid synthesis blocked DNS and RNS synthesis suppressed Blocking the one methyl cycle (SAM SAH translation stops) Methylation of more than one hundred molecules blocked (DNA, RNA methylation; phospholipid synthesis myelin; catecholamine...)

17 Vitamin B12 deficiency laboratory findings Blocking the folate cycle (methyl-thf THF process stops) Pernicious anemia (megaloblastic hemopoiesis, MCV increase, reticulocyte depletion) Increased methylmalonic acid (MMA) level in serum and in urine Low serum folate level and sometimes low Holo-transcobalamin (HTC) level Blocking the one methyl cycle (SAM SAH translation stops) Serum homocystein (HCy) elevation Increased methylmalonic acid (MMA) level in serum and in urine Serum cholesterol and LDL-cholesterol elevation Low HTC level and sometimes low serum folate level Normal or low serum total B12 level

18 Vitamin B12 deficiency consequences (proved) Megaloblastic anemia Pernicious anemia Vitamin B12 deficiency syndrome Dementia Ataxia (muscular ataxia, spasm) Paresthesia Incontinency Low blood pressure Psychiatric syndromes (depression, paranoid episodes, affective lability) Cognitive deficiency

19 Vitamin B12 deficience consequences (proposed) Alzheimer syndrome, Alzheimer disease, Lewy body dementia, pre-senile dementia Breast cancer (adenocarcinoma) Cardiovascular diseases (via elevated homocystein level) Osteoporosis (via EGF / TNF regulation) Cataract, macula-degeneration General fatigue syndrome, connected to chronic malignant diseases Inadequate intrauterine fetal brain development

20 B12 Folate deficiency most affected groups Vegetarians, vegans Since B12 source is only animal food, vegan diet always develop B12 deficiency. Plants, fungi and algae could not fill the gap, vegans must use B12 supplements Age above 50 years The B12 absorption from food is more-and more affected by aging, additional B12 supplementation is recommended. Regular alcohol consumption Not alcoholism just a social drinking could deplete liver B12 reserve.

21 B12 Folate deficiency most affected groups Reflux disease, chronic gastric inflammation, helicobacter pylori infection Basic therapy for such situation is the use of PPI or H2 receptor antagonists. If the HCl concentration is low, it will decrease the B12 absorption. Diabetes and/or some autoimmune diseases Absorption is affected, and/or Methformin therapy will decrease the B12 absorption.

22 Vitamin B12 supplementation Oral supplementation is recommended High dose (minimally 500 µg daily) Together with folate (vitamin B9) and piridoxin (vitamin B6) B Capsule developed 4 years ago, for supplementation B µg B9 (Folate) 800 µg B µg

23 B Capsule - effects High serum homocystein level: significant decrease of HCy level after 4 weeks of usage High cholesterol: 20-25% decrease of serum cholesterol after 4 weeks of usage Pre-senile dementia: better cognitive status, less psychotic events (paranoid, affective lability), better sleep, better short memory Ongoing clinical trial for HCy cholesterol: will end in late 2018.

24 B Clinical Trial (pilot data) Serum cholesterol, mean + SD, N= 42 Holotranscobalamin (B12) High Low Total High 6,8 (1,0) 6,9 (0,7) 6,9 (0,8) Homocystein Low 5,3 (0,5) 6,1 (0,5) 5,4 (0,5) Total 5,8 (1,0) 6,8 (0,7) 6,2 (1,0)

25 B Clinical Trial (pilot data) Serum cholesterol, mean + SD, N= 42 Holotranscobalamin (B12) High Low Total High 6,8 (1,0) 6,9 (0,7) 6,9 (0,8) Homocystein Low 5,3 (0,5) 6,1 (0,5) 5,4 (0,5) Total 5,8 (1,0) 6,8 (0,7) 6,2 (1,0)

26 B Clinical Trial (pilot data) pmol/l Serum holotranscobalamin, mean + SD, N= Kategória 1 O day 30 days 90 days B supplementation

27 B Clinical Trial (project plan) Patients with elevated homocystein and cholesterol, with low holotranscobalamin One arm: 90, 180 and 360 days treatement with B Control arm: Placebo treatment for 90 and 180 days Measurement: homocystein + total cholesterol + holotranscobalamin Planned timing: 2017 Q Q4

28 Köszönöm. Hvala. Thank you.