CLINICAL PHARMACOLOGY
Mechanism Of Action
Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA)
have an important role in brain and central nervous system development and
functioning1-4. Decreased omega-3 fatty acids levels, mainly DHA and
EPA, are associated with the occurrence of psychiatric, neurodegenerative, and
other neurodevelopmental disorders such as dyspraxia, dyslexia, autism³,
peroxisomal disorders5, Alzheimer's disease6, and ADHD3,
Administration of phosphatidylserine {PS} enriched with omega-3 fatty acids was
found to significantly increase DHA level in rat brains7.
While the exact mechanism by which Vayarin® exerts its
effects is not fully understood, PS present in the mammalian nervous system,
which is charactenzed by its substantial levels of omega-3 fatty acids, has
been implicated in numerous membrane related functions, such as maintaining the
integrity of cell membranes, cell excitability, cell-to-cell recognition and communication8.
PS has been found to regulate key proteins in neuronal membranes, including
sodium/calcium ATPase9 and protein kinase C10 which
undertake crucial functions in diverse signal transduction pathways. Similarly,
PS interacts with Raf-1 protein kinase to promote a cascade of reactions that
are believed to be involved in cell survival11. Additionally, PS has
been found to influence neurotransmitter activity, such as the release of
acetylcholine, dopamine and noradrenaline12,13 and to increase brain
glucose levels.
Absorption and Metabolism
Fallowing dietary ingestion of phospholipids, pancreatic
digestive enzymes cleave specific fatty acids, leading to the formation of lysophosphclipids
that are absorbed by the mucosal cells of the intest ne and could be reacylated
into phospholipids14. The fatty acids released can be furtJier used
for triglyceride synthesis. Because of the high activity of decarboxylases in
the mucosal cells, the majority of the PS is converted into other
phospholipids, primarily to phosphatidylethanolamine15. The
reacylated PS, phosphatidylethanolamine and other phospholipids enter the lympn
and circulation, and are redistributed.
Drug Interactions
PS can potentially interact with some anticholinergic and
cholinergic medications. It is recommended to consult with a physician about
Vayarin® interactions that may apply to specific medical conditions.
Toxicity
Vayarin®, similar to phosphatidylserine extracted from
bovine cortex (BC-PS), contains saturated and monounsaturated fatty acids as
well as ornega-3 LC-PUFA. The safety profile of BC-PS was determined in several
non-clinical studies. Repeat-dose safety studies in rats and dogs show that
oral administration of BC-PS at doses up to 1000 mg/kg/day for up to 6 months
was without any significant adverse effects of toxicological concern16.
The results of teratogenicity studies in rats at doses up to 200 mg/kg/day and
in rabbits at doses up to 450 mg/kg/day showed that oral administration of PS
did not affect embryonic and fetal development16. In a micronucleus
test, BC-PS was administered to mice at total dosages of 30,150 and 300 mg/kg in
two equal doses separated by 24-hours. The results of the study diu not reveal
any evidence of mutagenic potential or bone marrow toxicity16.
Clinical Experience17,18
Double-blind Study
Method
A 15-weeK, double-blind, placebo-controlled clinical trial
was conducted with 200 ADHD children randomized to receive either Vayarin® or
placebo (4 capsules/day). The effect of Vayarin® was assessed by rating scales
and questionnaires, including the Conners' parent (CRS-P) and teacher (CRS-T)
rating scales and the child health questionnaire (CHQ).
Results
162 participants completed the study, of whom 147 were
included in the efficacy analysis. Significant reduction in ADHD scores was
detected in the CRS-P assessment. In addition, a significant beneficial effect
was observed in the quality of life questionnaire {CHQ). Subgroup analysis of
children with a hyperactive/impulsive behavior, as well as mood and benavior-dysregulation,
revealed a more pronounced reduction in ADHD scores.
Open-label Extension
Method
A 15-week, open-label extension was conducted in 150
children with ADHD who completed the previously reported double-blind study.
Vayarin® (2 capsules) was administered daily. The effect of Vayarin® was
assessed by CRS-P,T and by the CHQ.
Results
Of 140 participants that completed the study, 127 were included
in the efficacy analysis. Children switching to Vayarin® (2 capsules/day) from
placebo treatment during the double-blind phase showed a significant reduction
in ADHD scores compared to baseline scores in the CRS-T and CRS-P.
Safety Evaluation
The treatment was generally well tolerated. There were no
clinically meaningful differences between treatment groups on the tested blood
parameters in the double-blind study and within the treatment group in the
open-label extension. In addition, no clinically significant findings were
observed during physical examination, vital signs or weight measurements m both
study phases (additional safety information is detailed in the Adverse Events
section).
REFERENCES
1. Richardson, A.J., 0meqa-3 fatty acids in ADHD and
related neu rod eve I op mental disorders. Irrt Rev Psychiatry, 2006. 13(2): p.
15W2.
2. SanGiovanni, J.P., et al., Meta-analysis of dietary
essential fatly acids and long-chain polyunsaturated fatty acids as they relate
to visual resolution acuity in healthy preterm infants. Pediatrics,
2000.105(6): p. 1292-8.
3. Schuchardt, J.P., et al., Significance of long-chain polyunsaturated
fatty acids (PUFAs) for the development and behaviour of children. Eur J
Pediatr, 2010.169(2): p. 149-64.
4. Kawashima, A., et al., Effects of eicosapentaenoic
acid on synaptic plasticity. fatty acid profile and phosphoiinositide 3-kinase
signaling in rat hippocampus and differentiated PC12 cells. J Nutr Biochern,
2010.21(4): p. 268-77.
5. Martinez, M.â Severe deficiency of docosahexaenoic
acid in Beroxisomal disorders: a defect of delta 4 desaturation? eurology,
1990. 40(8): p. 1292-8.
6. Soderberg, M., et al., Fatty acid composition of brain
phospholipids in aqinq and in Alzheimer's disease. Lipids, 1991.26(6): p.
421-5.
7. Vaisman, N., Pelled, D., n-3 phosphatidyl serine
attenuated scopolamine-induced amnesia in middle-aged rats. Prog Neuropsychopharmacol
Biol Psychiatry, 2009.33(6): p. 952-9..
8. Mozzi, R., Buratta, S., Goracci, G., Metabolism and functions
of phosphatidylserine in mammalian brain. Neurochem Res, 2003. 28(2): p.
195-214.
9. Wheeler, R.P.W., R., ATPase activity of the sodium
pump needs of phosphatidylserine. Nature, 1970. 225(5231): p. 449-450.
10. Bittova, L., Stahelin, R.V., Cho, W., Roles of ionic
residues of the C1 domain in protein kinase C-alpha activation and the origin
of phosphatidylserine specificity. J Biol Ghem. 2001. 276(6): p. 4218-26.
11. Vance, J.E., Phosphatidylserine and Phosphatidylethanolamine
in Mammalian Cells: Two Metabolically-related Aminophospholipids. ASBMB, 2008: p.
1-48.
12. Pepeu, G., Pepeu, I.M.,Amaducci, L., A review of phosphatidylserine
pharmacological and clinical effects. Is phosphatidylserine a drug for the
ageing brain? Pharmacol Res, 1996.33(2): p. 73-80.
13. Mazzari, S. and A. Battistella, Phosphatidylserine
effects on dopamine release from striatum synaptosomes. In: Multidisciplinary
Approach to Brain Development. Elsevier North Holland Amsterdam, 1980: p.
569-570.
14. Tso, P., Intestinal lipid absorption. Physiology of
the gastrointestinal tract, ed. L.R. Johnson. Vol. 56.1994, New York: Raven
Press.
15. Wise, E.M., Elwyn, D., Rates of reactions involved in
phosphatide synthesis in liver and small intestine of intact rats. Journal of
Biological Chemistry, 1965. 240: p. 1537-1548.
16. Heywood, R., Cozens, D., Richold, M., Toxicology of a
phosphatidylserine preparation from bovine brain. C. Trials Journal,
1987.24(1): p. 25-32.
17. Manor, I. et al., The effect of phosphatidylserine
containing omega-3 fatty-acids on attentiion-deficit hyperactivity disorder
symptoms in children: a double-blind placebo-controlled trial, followed by an
open-label extension. Eur Psychiatry, 2012.27(5): p.335-42.
18. Manor, I. et al., Safety of phosphatidylserine
containing omega-3 fatty acids in ADHD children: A double-blind placebo-controlled
trial followed by an open-label extension. Eur Psychiatry, 2013. Eur
Psychiatry, 2013. 28(6):p. 386-91.