rada16-i and Disease-Models--Animal

The Self-assembling Peptide Hydrogel [SAPH, PuraMatrix], a fully synthetic peptide solution designed to replace collagen, has recently been used to promote mucosal regeneration in iatrogenic ulcers following endoscopic submucosal dissection. Herein, we evaluated its utility in ulcer repair using a rat model of topical trinitrobenzene sulphonic acid [TNBS]-induced colonic injuries.. Colonic injuries were generated in 7-week-old rats by injecting an ethanol solution [35%, 0.2 mL] containing 0.15 M TNBS into the colonic lumen. At 2 and 4 days post-injury, the rats were subjected to endoscopy, and SAPH [or vehicle] was topically applied to the ulcerative lesion. Time-of-flight secondary ion mass spectrometry [TOF-SIMS] was used to detect SAPH. Colonic expression of cytokines and wound healing-related factors were assessed using real-time polymerase chain reaction or immunohistochemistry.. SAPH treatment significantly reduced ulcer length [p = 0.0014] and area [p = 0.045], while decreasing colonic weight [p = 0.0375] and histological score [p = 0.0005] 7 days after injury. SAPH treatment also decreased colonic expression of interleukin [IL]-1α [p = 0.0233] and IL-6[p = 0.0343] and increased that of claudin-1 [p = 0.0486] and villin [p = 0.0183], and β-catenin staining [p = 0.0237]. TOF-SIMS revealed lesional retention of SAPH on day 7 post-injury. Furthermore, SAPH significantly promoted healing in in vivo mechanical intestinal wound models.. SAPH application effectively suppressed colonic injury, downregulated inflammatory cytokine expression, and upregulated wound healing-related factor expression in the rat model; thus, it may represent a promising therapeutic strategy for IBD-related colonic ulcers.

Topics: Administration, Topical; Animals; Colitis, Ulcerative; Colon; Cytokines; Disease Models, Animal; Hydrogels; Male; Peptides; Rats; Rats, Sprague-Dawley; Wound Healing

To regenerate defected recurrent laryngeal nerves (RLNs), various methods have been developed. However, no consistently effective treatments are currently available because of their insufficient functional recovery. RADA16-I, a self-assembling peptide used clinically as a hemostat, reportedly supports neurite outgrowth and functional synapse formation in vitro. The purpose of this study was to investigate the effect of RADA16-I hydrogels on transected RLNs in rats.. Animal experiments with controls.. Fifteen adult rats were divided into the following three groups: RADA16-I (+), RADA16-I (-), and neurectomy. A 6-mm gap of the left RLN was bridged using an 8-mm silicone tube in the RADA16-I (-) and RADA16-I (+) groups. Subsequently, RADA16-I hydrogel was injected into the tube in the RADA16-I (+) group. The surgical incisions were closed without any further treatment in the neurectomy group. After 8 weeks, laryngoscopy and electrophysiological and histological examinations were performed to evaluate the effect of RADA16-I on nerve regeneration and thyroarytenoid muscle atrophy.. Although most rats in the three groups exhibited no improvements of their vocal fold movement, partial recovery was observed in one rat in the RADA16-I (+) group. The neurofilament-positive areas and the number of myelinated nerves in the RADA16-I (+) group were significantly higher than in the RADA16-I (-) group. The area of the left thyroarytenoid muscle in the RADA16-I (+) group was significantly larger than that of the neurectomy group.. Our results suggested that RADA16-I hydrogel was effective for RLN regeneration.. NA Laryngoscope, 130:2420-2427, 2020.

Topics: Animals; Disease Models, Animal; Laryngoscopy; Male; Nerve Regeneration; Peptides; Random Allocation; Rats; Rats, Sprague-Dawley; Recovery of Function; Recurrent Laryngeal Nerve

Topics: Animals; Cell Survival; Coated Materials, Biocompatible; Disease Models, Animal; Heart Failure; Heart Function Tests; Hydrogel, Polyethylene Glycol Dimethacrylate; Hydrogen-Ion Concentration; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Myocardial Infarction; Peptides; Pericardium; Rats, Inbred Lew; Rats, Sprague-Dawley

Localized and long-term delivery of growth factors has been a long-standing challenge for stem cell-based tissue engineering. In the current study, a polymeric drug depot-anchoring hydrogel scaffold was developed for the sustained release of macromolecules to enhance the differentiation of stem cells. Self-assembling peptide (RADA16)-modified drug depots (RDDs) were prepared and anchored to a RADA16 hydrogel. The anchoring effect of RADA16 modification on the RDDs was tested both in vitro and in vivo. It was shown that the in vitro leakage of RDDs from the RADA16 hydrogel was significantly less than that of the unmodified drug depots (DDs). In addition, the in vivo retention of injected hydrogel-incorporated RDDs was significantly longer than that of hydrogel-incorporated unmodified DDs. A model drug, vascular endothelial growth factor (VEGF), was encapsulated in RDDs (V-RDDs) as drug depot that was then anchored to the hydrogel. The release of VEGF could be sustained for 4weeks. Endothelial progenitor cells (EPCs) were cultured on the V-RDDs-anchoring scaffold and enhanced cell proliferation and differentiation were observed, compared with a VEGF-loaded scaffold. Furthermore, this scaffold laden with EPCs promoted neovascularization in an animal model of hind limb ischemia. These results demonstrate that self-assembling hydrogel-anchored drug-loaded RDDs are promising for localized and sustained drug release, and can effectively enhance the proliferation and differentiation of resident stem cells, thus lead to successful tissue regeneration.

Topics: Animals; Cell Differentiation; Cell Proliferation; Delayed-Action Preparations; Disease Models, Animal; Drug Delivery Systems; Drug Liberation; Endothelial Progenitor Cells; Female; Hindlimb; Humans; Hydrogels; Ischemia; Mice; Mice, Inbred BALB C; Mice, Nude; Neovascularization, Physiologic; Peptides; Tissue Engineering; Vascular Endothelial Growth Factor A

Self-assembling peptide (SAP) RADA16-I (Ac-(RADA)4-CONH2) has been suffering from a main drawback associated with low pH, which damages cells and host tissues upon direct exposure. In this study, we presented a strategy to prepare nanofiber hydrogels from two designer SAPs at neutral pH. RADA16-I was appended with functional motifs containing cell adhesion peptide RGD and neurite outgrowth peptide IKVAV. The two SAPs were specially designed to have opposite net charges at neutral pH, the combination of which created a nanofiber hydrogel (-IKVAV/-RGD) characterized by significantly higher G' than G″ in a viscoelasticity examination. Circular dichroism, Fourier transform infrared spectroscopy, and Raman measurements were performed to investigate the secondary structure of the designer SAPs, indicating that both the hydrophobic/hydrophilic properties and electrostatic interactions of the functional motifs play an important role in the self-assembling behavior of the designer SAPs. The neural progenitor cells (NPCs)/stem cells (NSCs) fully embedded in the 3D-IKVAV/-RGD nanofiber hydrogel survived, whereas those embedded within the RADA 16-I hydrogel hardly survived. Moreover, the -IKVAV/-RGD nanofiber hydrogel supported NPC/NSC neuron and astrocyte differentiation in a 3D environment without adding extra growth factors. Studies of three nerve injury models, including sciatic nerve defect, intracerebral hemorrhage, and spinal cord transection, indicated that the designer -IKVAV/-RGD nanofiber hydrogel provided a more permissive environment for nerve regeneration than the RADA 16-I hydrogel. Therefore, we reported a new mechanism that might be beneficial for the synthesis of SAPs for in vitro 3D cell culture and nerve regeneration.

Topics: Amino Acid Sequence; Animals; Axons; Cell Survival; Circular Dichroism; Disease Models, Animal; Green Fluorescent Proteins; Hydrogels; Hydrogen-Ion Concentration; Mice; Microscopy, Atomic Force; Models, Molecular; Molecular Sequence Data; Myelin Sheath; Nanofibers; Nerve Degeneration; Neural Stem Cells; Peptides; Protein Structure, Secondary; Rats, Sprague-Dawley; Rats, Transgenic; Spectroscopy, Fourier Transform Infrared

RADA16-I is a synthetic type I self-assembling peptide nanofiber scaffold (SAPNS) which may serve as a novel biocompatible hemostatic agent. Its application in neurosurgical hemostasis, however, has not been explored. Although RADA16-I is nontoxic and nonimmunogenic, its intrinsic acidity may potentially provoke inflammation in the surgically injured brain. We conducted an animal study to compare RADA16-I with fibrin sealant, a commonly used agent, with the hypothesis that the former would be a comparable alternative. Using a standardized surgical brain injury model, 30 Sprague-Dawley rats were randomized into three treatment groups: RADA16-I, fibrin sealant or gelatin sponge (control). Animals were sacrificed on day 3 and 42. Astrocytic and microglial infiltrations within the cerebral parenchyma adjacent to the operative site were significantly lower in the RADA16-I and fibrin sealant groups than control. RADA16-I did not cause more cellular inflammatory response despite its acidity when compared with fibrin sealant. Immunohistochemical studies showed infiltration by astrocytes and microglia into the fibrin sealant and RADA16-I grafts, suggesting their potential uses as tissue scaffolds. RADA16-I is a promising candidate for further translational and clinical studies that focus on its applications as a safe and effective hemostat, proregenerative nanofiber scaffold as well as drug and cell carrier.

Topics: Administration, Topical; Animals; Brain Injuries; Disease Models, Animal; Fibrin Tissue Adhesive; Hemostasis, Surgical; Hemostatics; Nanofibers; Neurosurgical Procedures; Peptides; Rats, Sprague-Dawley; Time Factors; Wound Healing

Ionic self-assembly of the peptide RADARADARADARADA (RADA16-1) may form a well-defined nanofiber and eventually a hydrogel scaffold, with a water content of over 99.5%. This leads to the establishment of a nanofiber barrier that can be used to achieve complete hemostasis in less than 20 s in multiple tissues and in a variety of different wounds. In the present study, the nanofiber scaffolds of RADA16-1 peptide were sonicated into smaller fragments to identify possible molecular mechanisms underlying the rapid cessation of bleeding associated with these materials. Atomic force microscopy (AFM), circular dichroism (CD), and rheometry were also used to evaluate the re-assembly kinetics of this peptide. A bleeding control experiment was performed in animal models to uncover the molecular mechanisms underlying this fast hemostasis. In this way, these sonicated fragments not only quickly reassembled into nanofibers indistinguishable from the original material, but the degree of reassembly was also correlated with an increase in the rigidity of the scaffold and increased as the time required for hemostasis increased.

Topics: Animals; Coagulants; Disease Models, Animal; Hemorrhage; Microscopy, Atomic Force; Models, Molecular; Nanofibers; Peptides; Protein Structure, Secondary; Rats