Epitalon (Epithalon)

Epitalon is a synthetic tetrapeptide, also known as AEDG peptide, composed of the amino acids Ala-Glu-Asp-Gly.(2) The peptide has been suggested to exhibit action similar to Epithalamin through several modes. Epithalamin is a related pineal peptide preparation containing Epitalon, which has been purported to potentially increase the average lifespan of various experimental models by 11-31% and may reduce mortality in murine models by a suggested 52%.(3) This potential mechanism and additional studies are outlined below.

Chemical Composition

• Molecular Formula: C14H22N4O9
• Molecular Weight: 390.34 g/mol
• Other Known Titles: Epitalon, Epithalone

A study investigated the potential mechanisms of Epitalon to influence gene expression and protein synthesis in stem cells such as gingival mesenchymal stem cells (hGMSCs). The study(2) has suggested that the peptide binds to histones - HI/6 and HI/3 - located at different sites in the tissue, which then interact with DNA. More specifically, the study posits that Epitalon may alter chromatin structure by specifically interacting with histones, thereby modulating gene expression. This interaction could imply that the peptide acts as a histone mimic, facilitating changes in chromatin dynamics. Epitalon's epigenetic regulation could involve competitive binding with histones at DNA interaction sites, increasing transcription of genes involved in neuronal differentiation. Such binding may displace other regulatory proteins, making DNA more accessible to transcriptional machinery, potentially inducing neuronal cell differentiation in periodontal ligament and retinal stem cells (hPDLSCs). This experimentation led to an upregulation of neurogenic differentiation markers, including Nestin, GAP43, β Tubulin III, and Doublecortin, in hGMSCs. Specifically, mRNA expression of these markers increased 1.6 to 1.8-fold. Considering the changes in these markers, the possible upregulation of neuronal differentiation and protein synthesis in retinal and ligament stem cells may lead to improved functionality.

A recent study suggested that Epitalon might reduce intracellular reactive oxygen species (ROS) levels in aged oocytes, potentially exhibiting antioxidant actions.(4) The peptide was suggested to significantly reduce ROS levels, unlike higher concentrations which did not demonstrate similar protective actions. Such reduction could be critical, as oxidative stress is considered a significant factor in cellular aging. Additionally, Epitalon may help preserve oocyte structural integrity. It was observed to possibly decrease fragmentation in post-ovulatory aged oocytes and during parthenogenetic activation, a process where an egg develops into an embryo without fertilization. The peptide also potentially maintains spindle integrity and correct cortical granule (CG) distribution. Spindles, crucial structures in cell division distributing chromosomes to daughter cells, and cortical granules, secretory vesicles important for preventing polyspermy (fertilization of an egg by multiple sperm), are essential for normal cell division and fertilization. Epitalon might correct spindle abnormalities and prevent incorrect CG placement, which are common issues in aged oocytes. Furthermore, Epitalon exposure was associated with potential improvements in mitochondrial function, vital for oocyte viability. Mitochondria, known as the cell's powerhouses, are considered crucial for ATP production and maintaining cellular metabolism. There were indications of improved mitochondrial membrane potential and an increase in mtDNA copy number, suggesting Epitalon might support mitochondrial integrity and functionality as oocytes age. Finally, the peptide was suggested to reduce DNA damage and apoptosis (cell death) in aged oocytes. It appeared to reduce the intensity of γH2AX signals, a marker of DNA damage, and seemed to decrease apoptosis rates, as indicated by reduced Annexin-V staining. These observations imply that Epitalon might enhance oocyte survival by potentially mitigating oxidative damage and preserving genomic stability, considered crucial for maintaining overall cell functionality.

To understand the anti-aging action of various synthetic peptides, studies have been widely conducted to study their potential in cell proliferation, cell regeneration and aging, cell apoptosis and matrix modeling.(5) It was suggested that Epitalon may inhibit MM-9 synthesis, which typically increases over time, and increase cell proliferation and regeneration process, which typically declines over time. More specifically, researchers postulated that the peptide may have “enhanced the expression of Ki-67 and CD98hc which are synthesized less intensely during cellular aging.” Epitalon also appeared to inhibit Caspase-3 activity, a crucial enzyme believed to facilitate apoptosis (programmed cell death). Researchers commented that the peptide “suppressed caspase-dependent apoptosis which increases during aging of cell cultures.” By potentially restricting Caspase-3 activity, Epitalon might support cell longevity and decrease apoptosis, enhancing its regenerative capabilities.

This study(6) was conducted to understand the proliferative potential of the peptide in fetal fibroblast cells. Pulmonary fibroblasts were isolated from the 24-week old fetus, and it was noted that these fibroblasts appeared to lose their proliferative function at passage 34. These cells possessed extremely small telomere sizes, smaller than they were originally during passage 10. When Epitalon was introduced in these otherwise aging cells, it appeared to stimulate telomere development, causing them to increase and restore their normal size. As a result of this size elongation, the telomeres seemed to cause 10 additional cell divisions than usually seen in control cells. Thus, this study suggested that Epitalon overcame the Hayflick limit and extended the normal cell cycle in the cells.(6)

In this clinical study,(7) lymphocytic cells were isolated and cultured from subjects aged between 76 and 80 years. The purpose of this study was to determine Epitalon action on ribosomal cell activity and its impact on heterochromatin de-condensation and polymorphism. The result of this study, following cell culture administration with Epitalon, was that the peptide appeared to induce activation of ribosomal genes and de-condensation of heterochromatin. Consequently, it appeared to induce the release of genes that were otherwise suppressed due to aging chromosomal regions. This study suggested that Epitalon might hold the potential to modify chromosomal regions in aging cells, activate chromatin, and restore cellular activities that were otherwise suppressed or delayed in geriatric subjects.

In this 2011 study,(8) three different mouse models were used to determine the peptide action on chromosomal aberrations. The three mouse models were: accelerated aging SAMP-1 female mice, and wild type SAMR-1 and SHR rats (both female mice). Upon Epitalon administration, it was observed that the incidence of the chromosomal aberrations in the bone marrow of accelerated aging SAMP-1 mice appeared to be nearly 2-fold higher than the other two models. When the peptide was introduced at 2 months in the mice, it appeared to decrease chromosomal aberrations in all three models, highest being in the accelerated cell aging SAMP-1 mice. When combined with melatonin at night, administered with water, there was no reported impact on peptide action. This study suggested that Epitalon may possess anti-mutagenic potential.

In this study,(9) one-year-old female mice (C3H/He) were observed with tumors in the reproductive organs (mammary glands and ovaries). Tumors in the mammary glands included various variants of the invasive ductal carcinogenic cells, whereas, in the ovaries, found tumors were granulosa cell tumors. These mice, kept effectively in standard conditions for six months, were divided into control and experimental groups. Epitalon was introduced five times a week. Upon study completion, it was reported that three out of nine mice in the control group appeared to exhibit metastasis and increased tumor cells. Meanwhile, peptide mice exhibited decreased number of tumor cells. Epitalon, upon administration, appeared to inhibit the metastasis process in the mice, suggesting potential anti-metastatic action.

In this study,(10) both young and old hypophysectomized birds were used to study the action of the Epitalon peptide on the morphology of the thymus gland. Hypophysectomized birds are birds in which the pituitary gland has been surgically removed. Upon peptide administration, it was discovered that the morphology of the thymus gland appeared to be restored in all birds, regardless of their age. The most improved results were observed in birds (primarily chickens) that underwent neonatal hypophysectomy before the peptide was introduced.

This study(11) was conducted on aged monkeys to determine the actions of Epitalon on melatonin levels. With increasing age, melatonin levels tend to decrease due to reduced secretion, leading to difficulties in sleep regulation. This is primarily because the functioning of the pineal gland deteriorates with increasing age and a reduction in the amplitude of the hormonal circadian rhythm. Upon administration of Epitalon, it appeared to stimulate actions similar to those caused by the natural secretion of the pineal gland. Melatonin levels appeared to increase to "normal" levels.

In this clinical study,(12) it was suggested that when Epitalon was introduced in geriatric subjects, it appeared to elevate bioelectric and functional activities in the retina, thus preserving the morphological structure of the retina. More specifically, researchers postulated that the peptide "participates in common transcriptional mechanisms for the epiphysis and the retina." As a result, age-related retinal degeneration may be reversed in older subjects, which is supported by the positive clinical outcome in 90% of the subjects presented with the peptide.

This study(13) was conducted on 266 elderly subjects (over 60 years old) over 6 to 8 years, where some subjects were presented with the peptide-bioregulator Thymalin, others with Epitalon, and the rest with the combination of the two. After the study, it was observed that both peptides appeared to have the potential to restore basic bodily functions in geriatric subjects, including improved functions in the cardiovascular, endocrine, immune, and nervous systems, along with normalized metabolic and hemostatic activities. The peptide groups appeared to exhibit a 2-fold decrease in common geriatric disorders such as acute respiratory disorder, heart diseases, and bone disorders. In addition, the mortality rate in the subjects with peptides appeared to decrease significantly, with a 2-fold decrease in subjects with Thymalin, a 1.8-fold decrease in subjects with Epitalon, and a 2.5-fold decrease in subjects presented with both peptides.