Research Brief
What Is TB-500?
Resposta Rapida
Visao Geral TB-500 (tambem conhecido como Fequesetide) e um heptapeptideo sintetico correspondente a sequencia de aminoacidos N-acetilada 17–23 da proteina natural Timosina Beta-4 (Tβ4). Sua sequencia e Ac-LKKTETQ.[1][2] A molecula parental, Timosina Beta-4, e um polipeptideo ubiquo de 43 aminoacido...
Visao Geral
TB-500 (tambem conhecido como Fequesetide) e um heptapeptideo sintetico correspondente a sequencia de aminoacidos N-acetilada 17–23 da proteina natural Timosina Beta-4 (Tβ4). Sua sequencia e Ac-LKKTETQ.[1][2]
A molecula parental, Timosina Beta-4, e um polipeptideo ubiquo de 43 aminoacidos originalmente isolado da glandula timo. E encontrada em altas concentracoes em plaquetas sanguineas, globulos brancos e fluido de feridas, e pertence a familia β-timosina de proteinas sequestradoras de actina.[3]
O TB-500 foi desenvolvido com base na descoberta de que a sequencia especifica de sete aminoacidos (17–23) dentro da Tβ4 e responsavel por suas propriedades de ligacao a actina, que sao criticas para a migracao celular e o reparo tecidual. O fragmento mais curto mantem as atividades essenciais angiogenicas e de cicatrizacao de feridas da molecula parental, sendo mais economico de sintetizar.[6][8]
A FDA dos EUA classificou o TB-500 como uma Substancia Farmaceutica a Granel de Categoria 2, citando informacoes de seguranca insuficientes e risco de imunogenicidade. E proibido de ser manipulado por instalacoes de terceirizacao.[4] TB-500 e Tβ4 tambem sao explicitamente proibidos pela WADA sob a Secao S2.3 em todos os momentos.[5]
Referencias
- Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P. Synthesis and characterization do(a) N-terminal acetylated 17-23 fragment of thymosin beta 4 identificado(a) in TB-500. Drug Testing and Analysis. 2012;4(9):733-738.
- Delcourt V, Garcia P, Chabot B, Bailly-Chouriberry L. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Testing and Analysis. 2022;14(12):1963-1969.
- Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opinion on Biological Therapy. 2012;12(1):37-51.
- U.S. Food and Drug Administration. Certain Substancia Farmaceutica a Granels for Use in Compounding que May Present Significant Safety Risks. FDA.gov. Updated July 8, 2025.
- World Anti-Doping Agency. The 2025 Lista de Substancias Proibidas. WADA. January 1, 2025.
- Xing Y, Ye Y, Zuo H, Li Y. Progress no(a) Function and Application of Thymosin β4. Frontiers in Endocrinology. 2021;12:767785.
- Bock-Marquette I, Maar K, Maar S, et al. Thymosin beta-4 denotes novo(a) directions towards developing prosperous anti-envelhecimento regenerative therapies. International Immunopharmacology. 2023;116:109741.
- Philp D, Badamchian M, Scheremeta B, Nguyen M, Goldstein AL, Kleinman HK. Thymosin β4 e um(a) synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db camundongos diabeticos e em camundongos idosos. Wound Repair and Regeneration. 2003;11(1):19-24.
- Belsky JB, Rivers EP, Filbin MR, Lee PJ, Morris DC. Thymosin beta 4 regulacao of actin in sepse. Expert Opinion on Biological Therapy. 2018;18(sup1):193-197.
- Hinkel R, El-Aouni C, Olson T, et al. Thymosin beta4 e um(a) essencial paracrine factor of embryonic endothelial progenitor cell-mediated cardioprotecao. Circulation. 2008;117(17):2232-2240.
- Bock-Marquette I, Saxena A, White MD, Dimaio JM, Srivastava D. Thymosin beta4 ativa integrin-linked kinase and promove cardiac migracao celular, survival and cardiac repair. Nature. 2004;432(7016):466-472.
- Smart N, Risebro CA, Melville AA, et al. Thymosin β4 induz adult epicardial progenitor mobilization and neovascularizacao. Nature. 2007;445(7124):177-182.
- Sosne G, Kleinman HK. Primary Mechanisms of Thymosin β4 Repair Activity in Dry Eye Disorders and Other Tissue Injuries. Investigative Ophthalmology & Visual Science. 2015;56(9):5110-5117.
- Reyes-Gordillo K, Shah R, Popratiloff A, et al. Thymosin-β4 (Tβ4) Blunts PDGF-Dependent Phosphorylation and Binding of AKT to Actin in Hepatic Stellate Cells. American Journal of Pathology. 2011;178(5):2100-2108.
- Malinda KM, Sidhu GS, Mani H, et al. Thymosin beta 4 acelera cicatrizacao de feridas. Journal of Investigative Dermatology. 1999;113(3):364-368.
- Shah R, Reyes-Gordillo K, Cheng Y, et al. Thymosin β4 Prevents Oxidative Stress, Inflammation, and Fibrosis in Ethanol- and LPS-Induced Liver Injury in Mice. Oxidative Medicine and Cellular Longevity. 2018;2018:9630175.
- Rahaman KA, Muresan AR, Min H, et al. Simultaneous quantification of TB-500 e seu(sua) metabolites by UHPLC-Q-Exactive orbitrap MS/MS e seus(suas) screening by cicatrizacao de feridas activities in-vitro. Journal of Chromatography B. 2024;1235:124033.
- Malinda KM, Sidhu GS, Mani H, et al. Thymosin beta 4 acelera cicatrizacao de feridas. Journal of Investigative Dermatology. 1999;113(3):364-368.
- Sosne G, Ousler GW. Thymosin beta 4 ophthalmic solution for dry eye: a randomizado, controlado por placebo, Phase II ensaio clinico. Clinical Ophthalmology. 2015;9:877-884.
- Sosne G, Dunn SP, Kim C. Thymosin β4 Significantly Improves Signs and Symptoms of Severe Dry Eye in a Phase 2 Randomized Trial. Cornea. 2015;34(5):491-496.
- Bao W, Ballard VL, Needle S, et al. Cardioprotection by sistemico(a) dosing of thymosin beta four apos ischemic myocardial injury. Frontiers in Pharmacology. 2013;4:149.
- Treadwell T, Kleinman HK, Crockford D, et al. The regenerative peptide thymosin β4 acelera a taxa of dermal healing in preclinical modelo animals e em patients. Annals do(a) New York Academy of Sciences. 2012;1270:37-44.
- Nguyen J, Verma S, Vuong VT, et al. Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing. Investigative Ophthalmology & Visual Science. 2025;66(14):31.
- Sosne G, Qiu P, Goldstein AL, Wheater M. Biological activities of thymosin beta 4 defined by ativo(a) sites in short peptide sequences. The FASEB Journal. 2010;24(7):2144-2151.
- Ho EN, Kwok WH, Lau MY, et al. Doping control analysis of TB-500 in equine urine and plasma by liquid chromatography-mass spectrometry. Journal of Chromatography A. 2012;1265:57-69.
- Kwok WH, Leung GN, Wan TS, et al. Doping control analysis of seven peptide hormones in horse plasma and urine by liquid chromatography-mass spectrometry. Analytical and Bioanalytical Chemistry. 2013;405:2653-2667.
- Smart N, Risebro CA, Melville AA, et al. Thymosin β4 induz adult epicardial progenitor mobilization and neovascularizacao. Nature. 2007;445(7124):177-182.
- RegeneRx Biopharmaceuticals. Phase I Safety Trial for RGN-352: Injectable Thymosin Beta 4. 2009.
- Treadwell T, Kleinman HK, Crockford D, et al. The regenerative peptide thymosin β4 acelera dermal healing. Annals do(a) New York Academy of Sciences. 2012;1270:37-44.
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