The cornea is the outer thin layer of epithelial cells protecting the eye. After wounding, timely resurfacing of the cornea with new cells is critical, to prevent loss of normal function and loss of vision. Corneal epithelial healing occurs in stages, with cells migrating, dividing and differentiating. Therapies for corneal injury are limited. Therefore, the recent finding that Tb4 promotes corneal wound repair in animal models offers hope for a therapeutic product that will improve the clinical outcome of patients with injured corneas.
TB-500 was identified as a gene that was up-regulated four-to-six fold during early blood vessel formation and found to promote the growth of new blood cells from the existing vessels. This peptide is present in wound fluid and when administered subcutaneously, it promotes wound healing, muscle building and speeds up recovery time of muscles fibres and their cells. An additional key factor of TB-500 is that it promotes cell migration through a specific interaction with actin in the cell cytoskeleton. It has been demonstrated that a central small amino acid long-actin binding domain has both blood cell reproduction and wound healing characteristics. These characteristics are uncovered by accelerating the migration of endothelial cells and keratinocytes. It also increases the production of extracellular matrix-degrading enzymes.
A critical step in wound healing is angiogenesis. New vessels are needed to supply nutrients and oxygen to the cells involved in repair, to remove toxic materials and debris of dead cells and generate optimal conditions for new tissue formation. Another important step is the directional migration of cells into the injured area, joining up to repair the wound. This requires an attractant that will direct the cells to the wound and propel them to the site. These critical steps in wound healing are regulated by beta 4, as seen in the following experiments.
Beta thymosins are a family of proteins which have in common a sequence of about 40 amino acids similar to the small protein thymosin β4. They are found almost exclusively in multicellular animals. Thymosin β4 was originally obtained from the thymus in company with several other small proteins which although named collectively "thymosins" are now known to be structurally and genetically unrelated and present in many different animal tissues.
Froemke's study1, published in April, showed that oxytocin temporarily suppresses inhibitory neurons — those that dampen neural activity — which allows excitatory cells to respond more strongly and reliably. “Our hypothesis is that the virgin brain is a blanket of inhibition, and that pairing the pup calls with oxytocin allows the network to be reconfigured,” says Froemke. The hormone may serve to amplify incoming signals and allow them to be recognized as behaviourally important. (It is at least possible, he says, that this same mechanism could explain why some human mothers feel they are uniquely tuned to a baby's cries.)
The need to balance hunting pride and social obligations, and the necessity to reconnect with a family that depends on their provisioning were likely experienced by men throughout much of human evolutionary history. Oxytocin is found in all mammals and originated in the mother-infant bond, where it helps with childbirth, nursing and bonding. In some species, this existing hormonal mechanism could then be harnessed for novel contexts – for instance, men investing in pair-bonding and family provisioning, which is rare among mammals.
Osteoclast differentiation was assessed by tartrate-resistant acid phosphatase (TRAP) staining and activity. After 5 days of culture, cells were stained for TRAP kit using a leukocyte acid phosphatase kit (Sigma Aldrich, St Louis, MO, USA). Cells with three or more nuclei were counted as multinucleated mature osteoclasts. To measure TRAP activity, cells were fixed with 10% formalin for 10 min and 95% ethanol for 1 min, and then 100 μl of citrate buffer (50 mM, pH 4.6) containing 10 mM sodium tartrate and 5 mM p-nitrophenylphosphate (Sigma-Aldrich) was added to the wells containing fixed cells in the 48-well plates. After incubation for 1 h, enzyme reaction mixtures in the wells were transferred to new plates containing an equal volume of 0.1 N NaOH. Absorbance was measured at 410 nm using a microplate reader.
There have been encouraging results for the use of Tβ4 as a topical gel to treat venous stasis ulcers, a type of wound that develops on the lower leg of patients with chronic vascular disease. Two other reports indicated that Tβ4, formulated in eye-drops, may enhance corneal wound healing in diabetic patients, and improve ocular discomfort. These are the most advanced trials to date. As of yet, despite promising animal models, there has been no significant study exploring the efficacy of intravenous Tβ4 injections in treating ischemic heart injury.
Silencing of the Tβ4 or Wnt5a gene was achieved by transfecting cells with small interfering RNA (siRNA). Cells were transfected with Tβ4 or Wnt5a siRNAs (30 nM) for 24 hours using Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA) according to the manufacturer's instructions. Cells were transfected with Silencer negative control siRNA using the same protocol.
“Further analysis by gender revealed that females in the 5-HTP group had a significantly lower panic rate and intensity of cognitive symptoms whereas, in males, the effect of 5-HTP was limited to lowering the intensity of somatic panic symptoms. Thus, an increased availability of 5-HT may have a gender-dependent protective effect in CCK-4-induced panic.”
5-HTP is sold over the counter in the United States, Canada, the Netherlands, and the United Kingdom as a dietary supplement for use as an antidepressant, appetite suppressant, and sleep aid. It is also marketed in many European countries for the indication of major depression under the trade names Cincofarm, Levothym, Levotonine, Oxyfan, Telesol, Tript-OH, and Triptum.