The musculoskeletal system, which is vital for movement, support, and protection, can be impaired by disorders such as osteoporosis, osteoarthritis, and muscular dystrophy. This review focuses on the advances in tissue engineering and regenerative medicine, specifically aimed at alleviating these disorders. It explores the roles of cell therapy, particularly Mesenchymal Stem Cells (MSCs) and Adipose-Derived Stem Cells (ADSCs), biomaterials, and biomolecules/external stimulations in fostering bone and muscle regeneration. The current research underscores the potential of MSCs and ADSCs despite the persistent challenges of cell scarcity, inconsistent outcomes, and safety concerns. Moreover, integrating exogenous materials such as scaffolds and external stimuli like electrical stimulation and growth factors shows promise in enhancing musculoskeletal regeneration. This review emphasizes the need for comprehensive studies and adopting innovative techniques together to refine and advance these multi-therapeutic strategies, ultimately benefiting patients with musculoskeletal disorders.

Polymer-based drug delivery technologies have revolutionized modern therapeutics by enabling controlled, sustained, and targeted drug release.

Peptide metabolites are emerging biomolecules with numerous possibilities in biomaterial-based regenerative medicine due to their inherent bioactivities. These small, naturally occurring compounds are intermediates or byproducts of larger proteins and peptides, and they can have profound effects, such as antiviral therapeutics, proangiogenic agents, and regenerative medicinal applications. This study is among the first to focus on using thymosin β4 protein-derived metabolites to pioneer novel applications for peptide metabolites in biomaterials. This study found that the novel peptide metabolite acetyl-thymosin β4 (amino acid 1–17) (Ac-Tβ_1-17) exhibited significant protease inhibition activity against SARS-CoV-2, surpassing its precursor protein. Additionally, Ac-Tβ_1-17 demonstrated beneficial effects, such as cell proliferation, wound healing, and scavenging of reactive oxygen species (ROS) in human umbilical vein endothelial cells (HUVEC). Integrating Ac-Tβ_1-17 into a peptide-based scaffold facilitated cell growth and angiogenesis inside the scaffold and through gradual release into the surrounding environment. The Ac-Tβ_1-17 peptide treatment induced significant biochemical responses in HUVEC, increasing Akt, ERK, PI3K, MEK, and Bcl-2 gene expression and proangiogenic proteins. Ac-Tβ_1-17 peptide treatment showed similar results in ex vivo by enhancing mouse fetal metatarsal growth and angiogenesis. These findings highlight the potential of natural protein metabolites to generate biologically active peptides, offering a novel strategy for enhancing biomaterial compatibility. This approach holds promise for developing therapeutic biomaterials using peptide metabolites, presenting exciting prospects for future research and applications.

Modulating inflammatory cells in an implantation site leads to severe complications and still unsolved challenges for blood-contacting medical devices. Inspired by the role of galectin-1 (Gal-1) in selective functions on multiple cells and immunomodulatory processes, we prepared a biologically target-specific surface coated with the lipid bilayer containing Gal-1 (Gal-1-SLB) and investigate the proof of the biological effects. First, lipoamido-dPEG-acid was deposited on a gold-coated substrate to form a self-assembled monolayer and then conjugated dioleoylphosphatidylethanolamine (DOPE) onto that to produce a lower leaflet of the supported lipid bilayer (SLB) before fusing membrane-derived vesicles extracted from B16-F10 cells. The Gal-1-SLB showed the expected anti-fouling activity by revealing the resistance to protein adsorption and bacterial adhesion. In vitro studies showed that the Gal-1-SLB can promote endothelial function and inhibit smooth muscle cell proliferation. Moreover, Gal-1- SLB presents potential function for endothelial cell migration and angiogenic activities. In vitro macrophage culture studies showed that the Gal-1-SLB attenuated the LPS-induced inflammation and the production of macrophage-secreted inflammatory cytokines. Finally, the implanted Gal-1-SLB reduced the infiltration of immune cells at the tissue-implant interface and increased markers for M2 polarization and blood vessel formation in vivo. This straightforward surface coating with Gal-1 can be a useful strategy for modulating the vascular and immune cells around a blood-contacting device.

Thymosin β4 (Tβ4) was reported to exert various beneficial bioactivities such as tissue repair, anti‐inflammation, and reduced scar formation, and it is listed on the prohibited substances in sports by the World Anti‐Doping Agency. However, no metabolism studies of Tβ4 were reported yet. Previously, our lab reported in in vitro experiment that a total of 13 metabolites were found by using multiple enzymes, and six metabolites (Ac‐Tβ_31–43, Ac‐Tβ_17–43, Ac‐Tβ_1–11, Ac‐Tβ_1–14, Ac‐Tβ_1–15, and Ac‐Tβ_1–17) were confirmed by comparing with the synthetic standards. This study was aimed at identifying new metabolites of Tβ4 leucine aminopeptidase (LAP), human kidney microsomes (HKM), cultured huvec cells, and rats after administration of Tβ4 protein to develop biomarkers for detecting doping drugs in sports. A method for detecting and quantifying Ac‐Tβ_1–14 was developed and validated using Q‐Exactive orbitrap mass spectrometry. The limit of detection (LOD) and limit of quantification (LOQ) of the Ac‐Tβ_1–14 were 0.19 and 0.58 ng/mL, respectively, and showed a good linearity (r² = 0.9998). As a result, among the six metabolites above, Ac‐Tβ_1–14, as a common metabolite, was found in LAP, HKM, huvec cells exposed to Tβ4, and the urine of rats intraperitoneally treated with 20‐mg/kg Tβ4. And the metabolite Ac‐Tβ_1–14 was quantitatively determined by 48 h in rats, with the highest concentration occurring between 0 and 6 h. Ac‐Tβ_1–14 was not detected in non‐treated control groups, including human blank urine. These results suggest that Ac‐Tβ_1–14 in urine is a potential biomarker for screening the parent Tβ4 in doping tests.

Bolasterone (7α,17α–dimethyltestosterone) and anabolic androgenic steroids are included in the World Anti‐Doping Agency's Prohibited list of substances. This study aimed to evaluate the metabolism of bolasterone through in vitro experiments using rat liver microsomes and in vivo experiments using rat urine after oral administration. Urine samples were collected over a 168‐h period. Bolasterone and its metabolites were detected by liquid chromatography coupled with a Q‐Exactive Obitrap mass spectrometry (LC‐HRMS). Ultimately 16 hydroxylated metabolites (M1–M16), one metabolite from the reduction of the 3‐keto function and 4‐ene (M17), and one glucuronic acid conjugated metabolite (M18) were detected. Metabolites M17 and M18 were confirmed by comparison with available reference or authentic standards. Metabolic modifications in the structure of the parent bolasterone result in different fragmentation patterns. Based on the sensitivity of the HRMS data, characteristic ions such as m/z 121.064 (C₈H₉O) generated from ring A of the mono‐hydroxylated metabolites and 121.101 (C₉H₁₃) generated from ring D of the di‐hydroxylated metabolites were observed that helped differentiate between the obtained metabolites. The structures of fragment ions were tentatively proposed based on their fragmentation pathways, where the significant ions were correlated to the possible structural fragments. In conclusion, new metabolites of bolasterone were detected and characterized by the use of the full‐scan and dd‐MS/MS using LC‐HRMS, and this data can be useful for providing metabolite information for the interpretation of mass spectra of anabolic bolasterone analogues for doping screening tests.