Sublingual Administration of Teucrium Polium-Loaded Nanofibers with Ultra-Fast Release in the Treatment of Diabetes Mellitus: In Vitro and In Vivo Evaluation

In this study, Teucrium polium (TP) methanolic extract, which has antidiabetic activity and protects the β-cells of the pancreas, was loaded in polyethylene oxide/sodium alginate nanofibers by electrospinning and administered sublingually to evaluate their effectiveness in type-2 diabetes mellitus (T2DM) by cell culture and in vivo studies. The gene expressions of insulin, glucokinase, GLUT-1, and GLUT-2 improved in TP-loaded nanofibers (TPF) on human beta cells 1.1B4 and rat beta cells BRIN-BD11. Fast-dissolving (<120 s) sublingual TPF exhibited better sustainable anti-diabetic activity than the suspension form, even in the twenty times lower dosage in streptozotocin/nicotinamide-induced T2DM rats. The levels of GLP-1, GLUT-2, SGLT-2, PPAR-γ, insulin, and tumor necrosis factor-alpha were improved. TP and TPF treatments ameliorated morphological changes in the liver, pancreas, and kidney. The fiber diameter increased, tensile strength decreased, and the working temperature range enlarged by loading TP in fibers. Thus, TPF has proven to be a novel supportive treatment approach for T2DM with the features of being non-toxic, easy to use, and effective.

Multifunctional Hydrogels for the Healing of Diabetic Wounds

The healing of diabetic wounds is hindered by various factors, including bacterial infection, macrophage dysfunction, excess proinflammatory cytokines, high levels of reactive oxygen species, and sustained hypoxia. These factors collectively impede cellular behaviors and the healing process. Consequently, this review presents intelligent hydrogels equipped with multifunctional capacities, which enable them to dynamically respond to the microenvironment and accelerate wound healing in various ways, including stimuli -responsiveness, injectable self-healing, shape -memory, and conductive and real-time monitoring properties. The relationship between the multiple functions and wound healing is also discussed. Based on the microenvironment of diabetic wounds, antibacterial, anti-inflammatory, immunomodulatory, antioxidant, and pro-angiogenic strategies are combined with multifunctional hydrogels. The application of multifunctional hydrogels in the repair of diabetic wounds is systematically discussed, aiming to provide guidelines for fabricating hydrogels for diabetic wound healing and exploring the role of intelligent hydrogels in the therapeutic processes.

Recent Advances in Functional Wound Dressings

Significance: Nowadays, the wound dressing is no longer limited to its primary wound protection ability. Hydrogel, sponge-like material, three dimensional-printed mesh, and nanofiber-based dressings with incorporation of functional components, such as nanomaterials, growth factors, enzymes, antimicrobial agents, and electronics, are able to not only prevent/treat infection but also accelerate the wound healing and monitor the wound-healing status. Recent Advances: The advances in nanotechnologies and materials science have paved the way to incorporate various functional components into the dressings, which can facilitate wound healing and monitor different biological parameters in the wound area. In this review, we mainly focus on the discussion of recently developed functional wound dressings. Critical Issues: Understanding the structure and composition of wound dressings is important to correlate their functions with the outcome of wound management. Future Directions: "All-in-one" dressings that integrate multiple functions (e.g., monitoring, antimicrobial, pain relief, immune modulation, and regeneration) could be effective for wound repair and regeneration.

Application progress of nanotechnology in regenerative medicine of diabetes mellitus

In recent years, the development of diabetic regenerative medicine has led to new developments and progress for the clinical treatment of diabetes mellitus and its various complications. Besides, the emergence of nanotechnology has injected new vitality into diabetic regenerative medicine. Nano-stent provides an appropriate direction for the regeneration of islet β cells, retinal tissue, nerve tissue, and wound tissue cells. Conductive nanomaterials promote various tissues' growth. Many nanoparticles also promote wound healing and present other advantages that have solved many potential problems in the practical application of regenerative medicine. In this review, we will summarize the application of nanotechnology in diabetic regenerative medicine.

Supramolecular Peptide Nanofiber Hydrogels for Bone Tissue Engineering: From Multihierarchical Fabrications to Comprehensive Applications

Bone tissue engineering is becoming an ideal strategy to replace autologous bone grafts for surgical bone repair, but the multihierarchical complexity of natural bone is still difficult to emulate due to the lack of suitable biomaterials. Supramolecular peptide nanofiber hydrogels (SPNHs) are emerging biomaterials because of their inherent biocompatibility, satisfied biodegradability, high purity, facile functionalization, and tunable mechanical properties. This review initially focuses on the multihierarchical fabrications by SPNHs to emulate natural bony extracellular matrix. Structurally, supramolecular peptides based on distinctive building blocks can assemble into nanofiber hydrogels, which can be used as nanomorphology-mimetic scaffolds for tissue engineering. Biochemically, bioactive motifs and bioactive factors can be covalently tethered or physically absorbed to SPNHs to endow various functions depending on physiological and pharmacological requirements. Mechanically, four strategies are summarized to optimize the biophysical microenvironment of SPNHs for bone regeneration. Furthermore, comprehensive applications about SPNHs for bone tissue engineering are reviewed. The biomaterials can be directly used in the form of injectable hydrogels or composite nanoscaffolds, or they can be used to construct engineered bone grafts by bioprinting or bioreactors. Finally, continuing challenges and outlook are discussed.

Antimicrobial Peptides: The Promising Therapeutics for Cutaneous Wound Healing

Chronic wound infections have caused an increasing number of deaths and economic burden, which necessitates wound treatment options. Hitherto, the development of functional wound dressings has achieved reasonable progress. Antibacterial agents, growth factors, and miRNAs are incorporated in different wound dressings to treat various types of wounds. As an effective antimicrobial agent and emerging wound healing therapeutic, antimicrobial peptides (AMPs) have attracted significant attention. The present study focuses on the application of AMPs in wound healing and discusses the types, properties and formulation strategies of AMPs used for wound healing. In addition, the clinical trial and the current status of studies on "antimicrobial peptides and wound healing" are elaborated through bibliometrics. Also, the challenges and opportunities for further development and utilization of AMP formulations in wound healing are discussed.

Heparin impairs skeletal muscle glucose uptake by inhibiting insulin binding to insulin receptor

Aim

Heparin, a widely used antithrombotic drug has many other anticoagulant-independent physiological functions. Here, we elucidate a novel role of heparin in glucose homeostasis, suggesting an approach for developing heparin-targeted therapies for diabetes.

Methods

For serum heparin levels and correlation analysis, 122 volunteer's plasma, DIO (4 weeks HFD) and db/db mice serums were collected and used for spectrophotometric determination. OGTT, ITT, 2-NBDG uptake and muscle GLUT4 immunofluorescence were detected in chronic intraperitoneal injection of heparin or heparinase (16 days) and muscle-specific loss-of-function mice. In 293T cells, the binding of insulin to its receptor was detected by fluorescence resonance energy transfer (FRET), Myc-GLUT4-mCherry plasmid was used in GLUT4 translocation. In vitro, C2C12 cells as mouse myoblast cells were further verified the effects of heparin on glucose homeostasis through 2-NBDG uptake, Western blot and co-immunoprecipitation.

Results

Serum concentrations of heparin are positively associated with blood glucose levels in humans and are significantly increased in diet-induced and db/db obesity mouse models. Consistently, a chronic intraperitoneal injection of heparin results in hyperglycaemia, glucose intolerance and insulin resistance. These effects are independent of heparin's anticoagulant function and associated with decreases in glucose uptake and translocation of glucose transporter type 4 (GLUT4) in skeletal muscle. By using a muscle-specific loss-of-function mouse model, we further demonstrated that muscle GLUT4 is required for the detrimental effects of heparin on glucose homeostasis.

Conclusions

Heparin reduced insulin binding to its receptor by interacting with insulin and inhibited insulin-mediated activation of the PI3K/Akt signalling pathway in skeletal muscle, which leads to impaired glucose uptake and hyperglycaemia.

Antioxidant biocompatible composite collagen dressing for diabetic wound healing in rat model

Associated with persistent oxidative stress, altered inflammatory responses, poor angiogenesis and epithelization, wound healing in diabetic patients is impaired. N-acetylcysteine (NAC) is reported to resist excess reactive oxygen species (ROS) production, prompt angiogenesis and maturation of the epidermis. Studies have revealed that graphene oxide (GO) can regulate cellular behavior and form cross-links with naturally biodegradable polymers such as collagen (COL) to construct composite scaffolds. Here, we reported a COL-based implantable scaffold containing a mixture of GO capable of the sustained delivery of NAC to evaluate the wound healing in diabetic rats. The morphological, physical characteristics, biocompatibility and NAC release profile of the GO-COL-NAC (GCN) scaffold were evaluated in vitro. Wound healing studies were performed on a 20 mm dorsal full-skin defect of streptozotocin (STZ)-induced diabetic rats. The injured skin tissue was removed at the 18th day post-surgery for histological analysis and determination of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) activity. In diabetic rats, we confirmed that the GCN scaffold presented a beneficial effect in enhancing the wound healing process. Additionally, due to the sustained release of NAC, the scaffold may potentially induce the antioxidant defense system, upregulating the expression levels of the antioxidant enzymes in the wound tissue. The findings revealed that the antioxidant biocompatible composite collagen dressing could not only deliver NAC in situ for ROS inhibition but also promote the wound healing process. This scaffold with valuable therapy potential might enrich the approaches for surgeon in diabetic wound treatment in the future.

Effects of Anti-Inflammatory Nanofibers on Urethral Healing

Protracted postsurgical inflammation leading to postoperative complications remains a persistent problem in urethral reconstruction. Nanofibers in the form of peptide amphiphiles expressing anti-inflammatory peptides (AIF-PA) have positively modulated local inflammatory responses. Urethroplasty is performed to repair 5 mm ventral urethral defects with: uncoated small intestinal submucosa (SIS); SIS dip-coated with AIF-PA1 (anti-inflammatory treatment), or SIS dip-coated with AIF-PA6 (control) on 12-week-old male Sprague Dawley rats (n = 6/group/timepoint). Animals are euthanized at 14 and 28 d postsurgery. Hematoxylin-eosin, Masson's Trichrome, and immunohistochemistry with primary antibodies against myeloperoxidase (MPO; neutrophils), CD68, CD86, CD206 (macrophages), and proinflammatory cytokines TNFα and IL-1β are performed. Complete urethral healing occurs in 3/6 uncoated SIS (50%), 2/6 SIS+AIF-PA6 (33.3%), and 5/6 SIS+AIF-PA1 (83.3%) animals at 14 d and all at 28 d. Application of AIF-PA1 to SIS substitution urethroplasty decreases MPO⁺ neutrophils, CD86⁺ M1 proinflammatory macrophages, TNFα, and IL-1β levels while concurrently increasing levels of CD206⁺ M2 proregenerative/anti-inflammatory macrophages at the anastomoses and the regenerated tissue at the wound bed (REGEN). AIF-PA1 treatment enhances the healing process, contributing to earlier, complete urethral healing, and increased angiogenesis. Further studies are needed to elucidate the specific mechanism of inflammatory response modulation on angiogenesis and overall urethral healing.

Self-Assembling Peptides as an Emerging Platform for the Treatment of Metabolic Syndrome

Metabolic syndrome comprises a cluster of comorbidities that represent a major risk of developing chronic diseases, such as type II diabetes, cardiovascular diseases, and stroke. Alarmingly, metabolic syndrome reaches epidemic proportions worldwide. Today, lifestyle changes and multiple drug-based therapies represent the gold standard to address metabolic syndrome. However, such approaches face two major limitations: complicated drug therapeutic regimes, which in most cases could lead to patient incompliance, and limited drug efficacy. This has encouraged scientists to search for novel routes to deal with metabolic syndrome and related diseases. Within such approaches, self-assembled peptide formulations have emerged as a promising alternative for treating metabolic syndrome. In particular, self-assembled peptide hydrogels, either as acellular or cell-load three-dimensional scaffoldings have reached significant relevance in the biomedical field to prevent and restore euglycemia, as well as for controlling cardiovascular diseases and obesity. This has been possible thanks to the physicochemical tunability of peptides, which are developed from a chemical toolbox of versatile amino acids enabling flexibility of designing a wide range of self-assembled/co-assembled nanostructures forming biocompatible viscoelastic hydrogels. Peptide hydrogels can be combined with several biological entities, such as extracellular matrix proteins, drugs or cells, forming functional biologics with therapeutic ability for treatment of metabolic syndrome-comorbidities. Additionally, self-assembly peptides combine safety, tolerability, and effectivity attributes; by this presenting a promising platform for the development of novel pharmaceuticals capable of addressing unmet therapeutic needs for diabetes, cardiovascular disorders and obesity. In this review, recent advances in developing self-assembly peptide nanostructures tailored for improving treatment of metabolic syndrome and related diseases will be discussed from basic research to preclinical research studies. Challenges facing the development of approved medicinal products based on self-assembling peptide nanomaterials will be discussed in light of regulatory requirement for clinical authorization.

The Hypoglycemic and Renal Protection Properties of Crocin via Oxidative Stress-Regulated NF-κB Signaling in db/db Mice

Background

As the main ingredient of Crocus sativus L. (Iridaceae) extract, crocin- I (CR) has been reported to show various pharmacological activities. The aim of this study was to investigate the hypoglycemic and renal protection properties of CR in db/db mice.

Methods

Eight-week-old db/db mice were treated with metformin (Met) (100 mg/kg) and CR (50 mg/kg) for eight weeks.

Results

CR treatment showed hypoglycemic functions indicated by reduced bodyweight, food and water intake, plasma glucose, and serum levels of glycated hemoglobin A1c. Additionally, the CR group showed increased serum levels of insulin and pyruvate kinase, hypolipidemic functions indicated by the suppressed levels of total cholesterol and triglyceride, and enhanced levels of high-density lipoprotein cholesterol, which are also indicators of hypoglycemic functions. The renal protection function of CR was demonstrated by its protection of renal structures and its regulation of potential indicators of nephropathy. The anti-oxidation and anti-inflammation effects of CR were verified by enzyme-linked immunosorbent assay. In the kidneys of db/db mice, CR decreased the expression of phospho-IκBα and phospho-nuclear factor-κB (NF-κB), whereas it enhanced the expression of nuclear respiratory factor 2, manganese superoxide dismutase 1, heme oxygenase-1, and catalase.

Conclusions

The anti-diabetic and anti-diabetic nephritic effects of CR were related to its modulation of oxidative stress-mediated NF-κB signaling.

Experimental models and methods for cutaneous wound healing assessment

Wound healing studies are intricate, mainly because of the multifaceted nature of the wound environment and the complexity of the healing process, which integrates a variety of cells and repair phases, including inflammation, proliferation, reepithelialization and remodelling. There are a variety of possible preclinical models, such as in mice, rabbits and pigs, which can be used to mimic acute or impaired for example, diabetic and nutrition-related wounds. These can be induced by many different techniques, with excision or incision being the most common. After determining a suitable model for a study, investigators need to select appropriate and reproducible methods that will allow the monitoring of the wound progression over time. The assessment can be performed by non-invasive protocols such as wound tracing, photographic documentation (including image analysis), biophysical techniques and/or by invasive protocols that will require wound biopsies. In this article, we provide an overview of some of the most often needed and used: (a) preclinical/animal models including incisional, excisional, burn and impaired wounds; (b) methods to evaluate the healing progression such as wound healing rate, wound analysis by image, biophysical assessment, histopathological, immunological and biochemical assays. The aim is to help researchers during the design and execution of their wound healing studies.

Renoprotective Effect of Formononetin by Suppressing Smad3 Expression in Db/Db Mice

PURPOSE

Glomerular sclerosis and renal interstitial fibrosis are the most important pathologies in the development of kidney damage under diabetic conditions. Smad3 plays antagonistic roles in high glucose-induced renal tubular fibrosis, which is an important treatment target for diabetic nephropathy (DN). Formononetin (FMN) has multiple effects on diabetic vascular complications including DN. However, whether it plays an anti-fibrosis role by regulating smad3 is unclear. The purpose of this study was to evaluate the renoprotective effect of FMN by suppressing smad3 expression in db/db mice.

METHODS

FMN was orally administered to db/db mice with a dose of 25 or 50 mg/kg/day for 8 weeks. At the end of the study, serum, urine, and kidney samples were collected for biochemical and pathological examinations. The expressions of proteins and mRNA associated with renal fibrosis were determined by biochemical, histological, immunofluorescence, and real-time PCR analysis.

RESULTS

The results showed that FMN substantially improved the glucolipid metabolism, reduced the oxidative stress, and protected renal function in db/db mice. Meanwhile, protein and mRNA expression of smad3 and related regulatory factor of extracellular matrix deposition were significantly suppressed.

CONCLUSION

The present study suggested that FMN has a good renoprotective effect in DN, which plays an anti-fibrosis role in db/db mice by suppressing the expression of smad3.

Emerging evidence for the roles of peptide in hypertrophic scar

Hypertrophic scar is a dermal fibroproliferative disorder characterized by excess collagen deposition. There are many existing treatment modalities, but none works perfectly in all individuals. Recently, evidence is increasing that peptides can play crucial roles in the prevention or treatment of hypertrophic scar. The peptides may be derived from growth factors, hormones, and intracellular products of proteolysis. In vitro and in vivo studies have revealed that a number of peptides, usually topically applied, have beneficial effects on fibroblasts in rat, mouse, hamster, pig and rabbit scar models. The length of such peptides typically ranges between 10 and 15 amino acids (aa). Peptides may reduce scar progenitors, prevent excessive scarring, decrease scar growth, speed re-epithelialization and promote scar maturation through multiple mechanisms. They may target TGF-β signaling, fibroblast function or collagen modulation, inflammation, renin angiotensin system, gap junction and other pathways. However, there is a paucity of evidence regarding specific binding sites for these peptides in scar models. Here, we review current research progress on the roles of peptides and underlying mechanisms in hypertrophic scar. We also discuss the clinical potential of peptides as therapeutic agents in scarring. Finally, the functions of several peptide-related compounds in hypertrophic scar are summarized.

The Antidiabetic and Antinephritic Activities of Auricularia cornea (An Albino Mutant Strain) via Modulation of Oxidative Stress in the db/db Mice

This study first systematically analyzed the constituents of an albino mutant strain of Auricularia cornea (AU). After 8 weeks of continuous treatment with metformin (Met) (0.1 g/kg) and AU (0.1 and 0.4 g/kg), db/db mice showed hypoglycemic functioning, indicated by reduced bodyweight, food intake, plasma glucose, serum levels of glycated hemoglobin A1c and glucagon, hepatic levels of phosphoenolpyruvate carboxykinase and lucose-6-phosphatasem, and increased serum levels of insulin. The effect of hypolipidemic functions were indicated by suppressed levels of total cholesterol and triglyceride, and enhanced levels of hepatic glycogen and high-density lipoprotein cholesterol. The renal protective effect of AU was confirmed by the protection in renal structures and the regulation of potential indicators of nephropathy. The anti-oxidative and anti-inflammatory effects of AU were verified by a cytokine array combined with an enzyme-linked immunosorbent assay. AU decreased the expression of protein kinase C α and β2 and phosphor-nuclear factor-κB, and enhanced the expression of catalase, nuclear respiratory factor 2 (Nrf2), manganese superoxide dismutase 2, heme oxygenase-1 and−2, heat shock protein 27 (HSP27), HSP60, and HSP70 in the kidneys of db/db mice. The results confirmed that AU's anti-diabetic and anti-nephritic effects are related to its modulation on oxidative stress.

Heparin-based and heparin-inspired hydrogels: size-effect, gelation and biomedical applications

The size-effect, fabrication methods and biomedical applications of heparin-based and heparin-inspired hydrogels are reviewed.

The Antidiabetic and Antinephritic Activities of Tuber melanosporum via Modulation of Nrf2-Mediated Oxidative Stress in the db/db Mouse

Tuber melanosporum (TM), a valuable edible fungus, contains 19 types of fatty acid, 17 types of amino acid, 6 vitamins, and 7 minerals. The antidiabetic and antinephritic effects of TM and the underlying mechanisms related to oxidative stress were investigated in db/db mice. Eight-week oral administration of metformin (Met) at 0.1 g/kg and TM at doses of 0.2 and 0.4 g/kg decreased body weight, plasma glucose, serum levels of glycated hemoglobin, triglyceride, and total cholesterol and increased serum levels of high-density lipoprotein cholesterol in the mice, suggesting hypoglycemic and hypolipidemic effects. TM promoted glucose metabolism by increasing the levels of pyruvate kinase and hepatic glycogen. It also regulated the levels of inflammatory factors and oxidative enzymes in serum and/or the kidneys of the mice. Additionally, TM increased the expression of nuclear respiratory factor 2 (Nrf2), catalase, heme oxygenase 1, heme oxygenase 2, and manganese superoxide dismutase 2 and decreased the expression of protein kinase C alpha, phosphor-janus kinase 2, phosphor-signal transducer and activator of transcription 3, and phosphor-nuclear factor-κB in the kidneys. The results of this study reveal the antidiabetic and antidiabetic nephritic properties of TM via modulating oxidative stress and inflammation-related cytokines through improving the Nrf2 signaling pathway.

Multidomain Peptide Hydrogel Accelerates Healing of Full-Thickness Wounds in Diabetic Mice

In vivo, multidomain peptide (MDP) hydrogels undergo rapid cell infiltration and elicit a mild inflammatory response which promotes angiogenesis. Over time, the nanofibers are degraded and a natural collagen-based extracellular matrix is produced remodeling the artificial material into natural tissue. These properties make MDPs particularly well suited for applications in regeneration. In this work, we test the regenerative potential of MDP hydrogels in a diabetic wound healing model. When applied to full-thickness dermal wounds in genetically diabetic mice, the MDP hydrogel resulted in significantly accelerated wound healing compared to a clinically used hydrogel, as well as a control buffer. Treatment with the MDP hydrogel resulted in wound closure in 14 days, formation of thick granulation tissue including dense vascularization, innervation, and hair follicle regeneration. This suggests the MDP hydrogel could be an attractive choice for treatment of wounds in diabetic patients.