4AA Preclinical
Livagen
Synthetic tetrapeptide bioregulator (Lys-Glu-Asp-Ala, KEDA) developed by the Khavinson group to reverse age-related chromatin compaction, reactivate silenced ribosomal genes, and restore protein-synthesis rhythms in aged hepatocytes and lymphocytes.
In Plain English:
Livagen is a four-amino-acid chain (Lysine – Glutamic acid – Aspartic acid – Alanine, abbreviated KEDA) synthesised as a defined Cytogen-class bioregulator by Professor Vladimir Khavinson's St. Petersburg Institute of Bioregulation and Gerontology. Its defining property is the reversal of age-related heterochromatinisation — the progressive silencing of genes through tightening of chromosomal packaging that accumulates across decades of ageing. In cultured lymphocytes from donors aged 75–88, Livagen decondensed pericentromeric structural heterochromatin on chromosomes 1 and 9, reactivated nucleolus organizer regions (ribosomal RNA gene clusters), and released genes that had been locked in repressed euchromatin, all without inducing cytotoxicity. In rat hepatocyte cultures, it restored the circadian amplitude of protein-synthesis oscillations that flatten with ageing, with the largest effect size in cells from the oldest animals. A separate enzyme study (PMID 12942748) found Livagen inhibited serum enkephalin-degrading enzymes with IC50 ≈ 20 µM — more potently than the standard inhibitors puromycin and leupeptin — without binding µ or δ opioid receptors directly, suggesting an indirect endogenous-opioid modulating role. In patients with atherosclerosis, Livagen combined with cobalt ions normalised elevated chromosomal aberration rates, aneuploidy, and polyploidy frequency, consistent with its chromatin-stabilising mechanism. The entire published evidence base is preclinical or ex-vivo; no controlled human RCTs exist and no pharmacokinetic data have been published.
Research Maturity
Preclinical (~8 peer-reviewed papers (2001–2022), all preclinical from one research network; no RCTs or independent replication+ Studies)
Focus
Cellular Repair
Healthy Aging
Immune Modulation
Origin
Developed by Professor Vladimir Kh. Khavinson and collaborators at the St. Petersburg Institute of Bioregulation and Gerontology (Northwestern Division, Russian Academy of Medical Sciences) as part of the Cytogen (defined-synthesis) programme. The peptide sequence Lys-Glu-Asp-Ala was derived from compositional analysis of liver and immune tissue fractions and first described in peer-reviewed literature in a 2002 Bulletin of Experimental Biology and Medicine chromatin study (PMID 12533768). CAS number 195875-84-4 is the primary registry entry; 402856-42-2 also appears in some vendor databases for the same compound. No patent or trade-name registration analogous to the original Cytogen capsule series (e.g., Ovagen®, Thymalin®) has been confirmed for Livagen in publicly searchable EU or US records; it is supplied predominantly as a research-grade lyophilised powder by Western vendors and as an unlicensed capsule in Russian/CIS markets.
Mechanism
Livagen's primary mechanism is chromatin remodelling via de-heterochromatinisation. Like other ultrashort Khavinson bioregulators, the tetrapeptide is small enough to traverse cell membranes and enter the nucleus via PEPT1/PEPT2 oligopeptide transporters or passive diffusion, where it interacts with histone proteins and DNA sequences — particularly TCGA-rich promoter motifs — through electrostatic and hydrogen-bond contacts. Key downstream actions: (1) Heterochromatin decondensation — Livagen selectively loosens pericentromeric constitutive heterochromatin on chromosomes 1 and 9 and facultative heterochromatin in aged euchromatic regions, restoring transcriptional access to silenced genes (PMID 12533768, PMID 16705247). (2) Ribosomal gene activation — reactivates nucleolus organizer region (NOR) ribosomal RNA genes, increasing nucleolar silver staining and ribosome biogenesis in aged lymphocytes. (3) Protein-synthesis rhythm restoration — rescues the ultradian (circumhoralian) oscillation of protein-synthesis rates in aged rat hepatocytes, the largest amplitude recovery occurring in 24-month-old animals (PMID 15926314). (4) Enkephalinase inhibition — inhibits serum dipeptidyl-peptidase-IV-like enzymes that degrade Met-enkephalin and Leu-enkephalin, with IC50 ≈ 20 µM (PMID 12942748), elevating endogenous opioid tone without direct receptor agonism. (5) Digestive enzyme modulation — oral administration in rats reduces intestinal glycyl-L-leucinedipeptidase by ~50% in young animals while increasing it in aged animals toward youthful baseline, consistent with age-specific compensatory normalisation (PMID 16075683). (6) Genomic stability — reduces chromosomal aberrations, aneuploidy, and polyploidy in atherosclerotic lymphocytes when combined with cobalt ions, reflecting stabilisation of chromatin architecture (PMID 25541832).
Outcome
Lymphocyte chromatin study (PMID 12533768, 2002, n = elderly donors): Livagen induced de-heterochromatinisation of pericentromeric heterochromatin, NOR reactivation, and gene release from age-condensed euchromatic regions; effects specific to elderly vs. young donor cells. Multi-peptide chromatin comparison (PMID 16705247, 2006, ages 75–88): Livagen and Epitalon — but not Vilon — induced deheterochromatinisation of pericentromeric heterochromatin on chromosomes 1 and 9; all three peptides induced total heterochromatin decondensation and ribosomal gene reactivation; anti-mutagenic protective effect against heavy metal (Co, Ni, Zn) induced chromosomal aberrations confirmed in both age groups. Enkephalinase inhibition (PMID 12942748, 2003): Livagen IC50 ≈ 20 µM vs. serum enkephalin-degrading enzymes, outperforming puromycin and leupeptin; no direct µ/δ opioid receptor binding detected in rat brain membranes. Hepatocyte protein synthesis (PMID 15926314, 2001, rats 1–24 months): Livagen increased protein synthesis amplitude in all age groups; maximal effect in 24-month (oldest) animals; Epitalon showed no corresponding hepatocyte effect. Digestive enzyme modulation (PMID 16075683, 2005): Two-week oral Livagen reduced glycyl-L-leucinedipeptidase 50% in young-rat small intestine; increased it in aged rats toward youthful levels; peptide resists intestinal enzymatic hydrolysis. Atherosclerosis genomic instability (PMID 25541832, 2014, atherosclerotic patients age 80+ vs. controls 30–35): Livagen + cobalt ions normalised elevated chromosomal aberrations, aneuploidy, and polyploidy; controls showed low baseline instability; atherosclerotic group showed high instability across all parameters, partially corrected by treatment. Zinc-binding / epigenetic metal interaction study (Springer IJPRT 2022): Livagen and Epitalon alone and combined with Ni, Co, Zn ions caused selective heterochromatinisation and deheterochromatinisation in lymphocytes from 71–86-year-olds; both peptides exerted anti-mutagenic protection against heavy-metal-induced chromosomal aberrations.
