TB-500 10mg Tissue regeneration

Le TB-500 lyophilisé non reconstitué se conserve au réfrigérateur (+2 à +8 °C), dans son emballage d'origine scellé, à l'abri de la lumière et de l'humidité ; pour un stockage long (plus de 3 mois), le congélateur (-20 °C) le garde jusqu'à 24 mois. A température refrigeree (2-8 degres Celsius), la stabilité documentee couvre au moins 12 mois. A température ambiante (en dessous de 25 degres Celsius), la durée recommandee pour un transport ou un stockage temporaire ne depasse pas 3 semaines. Une fois reconstitué avec de l'eau bacteriostatique pour preparation injectable, le TB-500 doit imperativement être conserve entre 2 et 8 degres Celsius. Sa stabilité post-reconstitution est documentee pour 30 jours maximum lorsque l'eau bacteriostatique (0,9 pourcent d'alcool benzylique) est utilisee. Avec de l'eau sterile sans conservateur, la fenetre d'utilisation se reduit a 7-10 jours. Le peptide est sensible aux cycles gel-degel repetes (limiter a trois maximum), a la lumiere UV directe, aux chocs thermiques et aux agitations vigoureuses qui peuvent denaturer la structure tertiaire. Preferer des aliquots pour les formats volumineux. Le certificat d'analyse est publié sur cette fiche, consultable avant de commander. La stabilité du TB-500 lyophilisé est élevée à -20°C sous dessiccation: > 24 mois sans perte mesurable de pureté RP-HPLC. En solution reconstituée (eau bactériostatique, 1-5 mg/mL), la stabilité est documentée 28 jours à 2-8°C en flacon ambré. Le pH optimal est neutre (6.5-7.5); éviter les solutions alcalines (> pH 8) qui favorisent la désamidation de Gln → Glu. Protéger strictement de la lumière UV. Ne jamais recongeler après reconstitution: les cycles gel/dégel génèrent des dimères/trimères détectables en SEC-HPLC. Conditionnement préféré: flacon verre borosilicaté type I, bouchon butyl siliconé, capsule aluminium flip-off.

TB-500 (Thymosin Beta-4 peptide, or active fragment of Tbeta-4) is a synthetic peptide derived from Thymosin Beta-4, a 44-amino-acid protein initially identified in the thymus and widely distributed across mammalian tissues. Most research suppliers offer either the full 1-44 sequence (Tbeta-4) or the active 17-23 fragment (LKKTETQ), the latter considered the key functional site responsible for several documented biological effects.

The established primary mechanism of TB-500 is G-actin (monomeric actin) sequestration via a specific binding site, which regulates actin-filamentary dynamics and cellular motility. This fundamental action influences the migration of fibroblasts, corneal keratocytes, endothelial progenitors, and epicardial cardiac progenitors in studied models.

Published work has documented several convergent secondary pathways. First, mobilization of endothelial progenitor cells (EPCs) from bone marrow to injury sites, observed in cardiac and vascular repair models. Second, upregulation of VEGF (Vascular Endothelial Growth Factor) and stimulation of local angiogenesis, critical for post-ischemic tissue revascularization. Finally, anti-inflammatory modulation via the NF-kappaB axis and documented reduction of pro-inflammatory markers (TNF-alpha, IL-1beta) in various murine models.

TB-500 is a synthetic 7-amino-acid fragment (Leu-Lys-Lys-Thr-Glu-Thr-Gln, LKKTETQ, 889.0 Da) corresponding to the active sequence of thymosin β-4 (Tβ4, 43 aa, 4960 Da), a ubiquitously expressed endogenous protein involved in the cytoskeleton. The canonical molecular mechanism of Tβ4 is monomeric G-actin sequestration via its β-thymosin domain (17-35), preventing premature polymerisation into F-actin filaments and freeing actin for rapid cytoskeletal rearrangements during cell migration. The LKKTETQ fragment (TB-500) partially retains this G-actin binding activity. Tβ4 also exerts anti-fibrotic effects via its N-terminal acetylated metabolite Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline, cleaved by prolyl-endopeptidase), which inhibits activated fibroblast proliferation and type I collagen accumulation. Documented signalling pathways include Integrin-Linked Kinase (ILK) activation, NF-κB downregulation, and modulation of several pro-regenerative microRNAs (miR-146a, miR-124).

The scientific corpus on Thymosin Beta-4 and its TB-500 fragment is dense and comes from several independent laboratories, particularly those of Allan Goldstein (GWU Washington), Ron Knutsen, and Hynda Kleinman (NIH). Main publications cover several converging models.

Philp and Kleinman (Annals of the New York Academy of Sciences 2007; DOI 10.1196/annals.1415.026) synthesized the first data on the regenerative properties of Tbeta-4 and its fragments, documenting promotion of endothelial migration, angiogenesis, and cutaneous healing in murine models of complex wounds.

Smart et al. (Nature 2011; DOI 10.1038/nature10188) published a major study showing that Tbeta-4 can reactivate adult epicardial cardiac progenitors in mice, with reduction of infarct size and improvement of left ventricular function post-MI. This work opened the way to several preclinical programs in regenerative cardiology.

In the ophthalmological field, Sosne et al. (Experimental Eye Research 2002; DOI 10.1006/exer.2001.1149) documented accelerated corneal re-epithelialization in rats after chemical injury, with improvement of clinical and histological parameters. These results were extended to dry eye and UV damage models.

Finally, Crockford (Annals of the New York Academy of Sciences 2007) synthesized data on the pharmacological profile, tissue distribution, and pharmacokinetics of TB-500 and Tbeta-4, positioning these peptides as serious research candidates in regenerative medicine. Several phase 2 clinical trials, run on full-length thymosin β4 and not on the TB-500 fragment, were conducted on Stevens-Johnson syndrome, corneal ulcer, and chronic skin lesions, with mixed results published by RegeneRx Biopharmaceuticals.

Corpus limitationsDespite existing phase 2 human data on full-length thymosin β4 (none on the TB-500 fragment), no definitive regulatory approval has been obtained. Reproducibility standards vary across laboratories and formulations. TB-500 remains strictly a preclinical research tool outside validated clinical trial protocols.