The chondrichthyan glucagon-like peptide 3 regulates hepatic ketone metabolism in the Pacific spiny dogfish Squalus suckleyi

Chondrichthyans have a novel proglucagon-derived peptide, glucagon-like peptide (GLP)-3, in addition to GLP-1 and GLP-2 that occur in other vertebrates. Given that the GLPs are important regulators of metabolic homeostasis across vertebrates, we sought to investigate whether GLP-3 displays functional actions on metabolism within a representative chondrichthyan, the Pacific spiny dogfish Squalus suckleyi. There were no observed effects of GLP-3 perfusion (10 nM for 15 min) on the rate of glucose or oleic acid acquisition at the level of the spiral valve nor were there any measured effects on intermediary metabolism within this tissue. Despite no effects on apparent glucose transport or glycolysis in the liver, a significant alteration to ketone metabolism occurred. Firstly, ketone flux through the perfused liver switched from a net endogenous production to consumption following hormone application. Accompanying this change, significant increases in mRNA transcript abundance of putative ketone transporters and in the activity of β-hydroxybutyrate dehydrogenase (a key enzyme regulating ketone flux in the liver) were observed. Overall, while these results show effects on hepatic metabolism, the physiological actions of GLP are distinct between this chondrichthyan and those of GLP-1 on teleost fishes. Whether this is the result of the particular metabolic dependency on ketone bodies in chondrichthyans or a differential function of a novel GLP remains to be fully elucidated.

Ketones provide an extra source of fuel for the failing heart without impairing glucose oxidation

BACKGROUND

Cardiac glucose oxidation is decreased in heart failure with reduced ejection fraction (HFrEF), contributing to a decrease in myocardial ATP production. In contrast, circulating ketones and cardiac ketone oxidation are increased in HFrEF. Since ketones compete with glucose as a fuel source, we aimed to determine whether increasing ketone concentration both chronically with the SGLT2 inhibitor, dapagliflozin, or acutely in the perfusate has detrimental effects on cardiac glucose oxidation in HFrEF, and what effect this has on cardiac ATP production.

METHODS

8-week-old male C57BL6/N mice underwent sham or transverse aortic constriction (TAC) surgery to induce HFrEF over 3 weeks, after which TAC mice were randomized to treatment with either vehicle or the SGLT2 inhibitor, dapagliflozin (DAPA), for 4 weeks (raises blood ketones). Cardiac function was assessed by echocardiography. Cardiac energy metabolism was measured in isolated working hearts perfused with 5 mM glucose, 0.8 mM palmitate, and either 0.2 mM or 0.6 mM β-hydroxybutyrate (βOHB).

RESULTS

TAC hearts had significantly decreased %EF compared to sham hearts, with no effect of DAPA. Glucose oxidation was significantly decreased in TAC hearts compared to sham hearts and did not decrease further in TAC hearts treated with high βOHB or in TAC DAPA hearts, despite βOHB oxidation rates increasing in both TAC vehicle and TAC DAPA hearts at high βOHB concentrations. Rather, increasing βOHB supply to the heart selectively decreased fatty acid oxidation rates. DAPA significantly increased ATP production at both βOHB concentrations by increasing the contribution of glucose oxidation to ATP production.

CONCLUSION

Therefore, increasing ketone concentration increases energy supply and ATP production in HFrEF without further impairing glucose oxidation.

Evaluation of High-Performance Polyether Ether Ketone Polymer Treated with Piranha Solution and Epigallocatechin-3-Gallate Coating

Background

Dental implantation has become a standard procedure with high success rates, relying on achieving osseointegration between the implant surface and surrounding bone tissue. Polyether ether ketone (PEEK) is a promising alternative to traditional dental implant materials like titanium, but its osseointegration capabilities are limited due to its hydrophobic nature and reduced surface roughness.

Objective

The aim of the study is to increase the surface roughness and hydrophilicity of PEEK by treating the surface with piranha solution and then coating the surface with epigallocatechin-3-gallate (EGCG) by electrospraying technique.

Materials and Methods

The study includes four groups intended to investigate the effect of piranha treatment and EGCG coating: a control group of PEEK discs with no treatment (C), PEEK samples treated with piranha solution (P), a group of PEEK samples coated with EGCG (E), and a group of PEEK samples treated with piranha solution and coated with EGCG (PE). Surface roughness, wettability, and microhardness were assessed through statistical analysis.

Results

Piranha treatment increased surface roughness, while EGCG coating moderated it, resulting in an intermediate roughness in the PE group. EGCG significantly improved wettability, as indicated by the reduced contact angle. Microhardness increased by about 20% in EGCG-coated groups compared to noncoated groups. Statistical analysis confirmed significant differences between groups in all tests.

Conclusion

This study demonstrates the potential of EGCG coating to enhance the surface properties of PEEK as dental implants. The combined piranha and EGCG modification approach shows promise for improved osseointegration, although further vivo research is necessary. Surface modification techniques hold the key to optimizing biomaterial performance, bridging the gap between laboratory findings and clinical implementation in dental implantology.

A balance of biocompatibility and antibacterial capability of 3D printed PEEK implants with natural totarol coating

OBJECTIVE

Polyetheretherketone (PEEK), a biomaterial with appropriate bone-like mechanical properties and excellent biocompatibility, is widely applied in cranio-maxillofacial and dental applications. However, the lack of antibacterial effect is an essential drawback of PEEK material and might lead to infection and osseointegration issues. This study aims to apply a natural antibacterial agent, totarol coating onto the 3D printed PEEK surface and find an optimized concentration with balanced cytocompatibility, osteogenesis, and antibacterial capability.

METHODS

In this study, a natural antibacterial agent, totarol, was applied as a coating to fused filament fabrication (FFF) 3D printed PEEK surfaces at a series of increasing concentrations (1 mg/ml, 5 mg/ml, 10 mg/ml, 15 mg/ml, and 20 mg/ml). The samples were then evaluated for cytocompatibility with L929 fibroblast and SAOS-2 osteoblast using live/dead staining and CCK-8 assay. The antibacterial capability was assessed by crystal violet staining, live/dead staining, and scanning electron microscopy (SEM) utilizing the oral primary colonizer S. gordonii and isolates of mixed oral bacteria in a stirring system simulating the oral environment. The appropriate safe working concentration for totarol coating is selected based on the results of the cytocompatibility and antibacterial test. Subsequently, the influence on osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and alizarin red staining (ARS) analysis of pre-osteoblasts.

RESULTS

Our results showed that the optimal concentration of totarol solution for promising antibacterial coating was approximately 10 mg/ml. Such surfaces could play an excellent antibacterial role by inducing a contact-killing effect with an inhibitory effect against biofilm development without affecting the healing of soft and hard tissues around FFF 3D printed PEEK implants or abutments.

SIGNIFICANCE

This study indicates that the totarol coated PEEK has an improved antibacterial effect with excellent biocompatibility providing great clinical potential as an orthopedic/dental implant/abutment material.

Construction of a layer-by-layer self-assembled rosemarinic acid delivery system on the surface of CFRPEEK implants for enhanced anti-inflammatory and osseointegration activities

Carbon fiber-reinforced polyether ether ketone (CFRPEEK) implants have attracted widespread attention in the field of clinical bone defect repair. However, the surface bioinertness confines the application of CFRPEEK implants. Inspired by the study of rosmarinic acid (RA)-promoted osteogenic differentiation, a self-assembly surface modification method based on electrostatic interactions, involving deposition of sodium carboxymethyl cellulose/chitosan and rosmarinic acid layer by layer on the surface of poly-L-lysine modified hydroxy CFRPEEK (SCPP/CC5@RA), is proposed to introduce RA on the surface of CFRPEEK for bioactivation. After layer-by-layer self-assembly (LBL), the surface of SCPP/CC5@RA exhibits weak electrophoresis (11.43 eV), suitable hydrophilicity, and bioactivity. The results of in vitro studies indicate that the RA release behavior of SCPP/CC5@RA effectively regulates the immune-inflammatory response and promotes the differentiation of osteoblasts. The rapid release of RA (0.17 μg mL-1) in the initial stage can downregulate the secretion of inflammation-related cytokines and significantly reduce oxidative stress levels; the sustained release of RA (0.06 μg mL-1) in the late stage can upregulate the expression of osteogenesis-related genes and induce mineralization of osteoblasts. Moreover, the rabbit tibia defect model demonstrates that the LBL technique can enhance the osseointegration of CFRPEEK implants. Compared with the control group, the bone trabecular thickness of the SCPP/CC5@RA group increases by 1.36 times, and the maximum pushing force increases by 2.67 times. In summary, this study provides a promising LBL based RA delivery system for the development of a dual-functional CFRPEEK implant in the field of bone implant biomaterials.

Bone ingrowth into a porous structure is achieved by preceding fibrogenesis and vascularization

Porous structures are frequently used in surgical implants to strengthen the interlocking power produced by bone ingrowth. Therefore, we aimed to elucidate the mechanism underlying bone ingrowth into a porous structure accompanied by vascularization. A nonbioactive polyetheretherketone implant with a 3D-printed porous structure was prepared and implanted in a bone hole created in the tibias of rabbits. We observed bone ingrowth in the same individual specimens immediately and at 2, 4, 8, and 12 weeks post-implantation using in-vivo computed tomography (CT). Furthermore, a detailed evaluation with blood vessels of each specimen at 2, 4, and 12 weeks was performed with ex-vivo CT and histological specimen. Additional histological evaluation was performed using thin sections of an implant made with thermoplastic polyurethane having the same structure. As a result, the bone invasion began after four weeks, when the construction of fibrous tissue and the spread of new blood vessels within the voids matured. As the bone matured in the load-bearing area, new blood vessels outside the bone matrix regressed. This longitudinal evaluation study suggests that preceding fibrogenesis and vascularization may be key in developing bone ingrowth. STATEMENT OF SIGNIFICANCE: A porous structure is an essential structure for dental and orthopedic implants because it provides strong fixation through bone invasion. Although it was known that vascularization was involved in this, the details were not known. This in vivo study revealed that in order for bone ingrowth to begin, a preparatory period of approximately 4 weeks was required to establish blood flow inside and outside the implant. Furthermore, it was confirmed that by spreading the fibrous structure in advance, it has an advantageous effect on the migration of cells involved in the formation of bones and blood vessels. We pointed out that it is necessary to consider fibrogenesis and vascularization when creating future implants.

Insights into the eradication of drug resistant Staphylococcus aureus via compound 6-nitrobenzo[cd]indole-2(1H)-ketone

6-Nitrobenzo[cd]indole-2(1H)-ketone (compound C2) exhibits an excellent germicidal effect against methicillin-resistant Staphylococcus aureus (MRSA). Mechanism studies show that C2 induces ROS over-production, cell membrane damage, and ATP and virulence factor down-regulation in bacteria. More importantly, C2 can inhibit biofilm formation and accelerate wound healing in a mouse infection model induced by MRSA.

Alteration of DNA methyltransferases by eribulin elicits broad DNA methylation changes with potential therapeutic implications for triple-negative breast cancer

Background: Triple-negative breast cancer (TNBC) is an aggressive disease with limited treatment options. Eribulin, a chemotherapeutic drug, induces epigenetic changes in cancer cells, suggesting a unique mechanism of action. Materials & methods: MDA-MB 231 cells were treated with eribulin and paclitaxel, and the samples from 53 patients treated with neoadjuvant eribulin were compared with those from 14 patients who received the standard-of-care treatment using immunohistochemistry. Results: Eribulin treatment caused significant DNA methylation changes in drug-tolerant persister TNBC cells, and it also elicited changes in the expression levels of epigenetic modifiers (DNMT1, TET1, DNMT3A/B) in vitro and in primary TNBC tumors. Conclusion: These findings provide new insights into eribulin's mechanism of action and potential biomarkers for predicting TNBC treatment response.

Methods to improve antibacterial properties of PEEK: A review

As a thermoplastic and bioinert polymer, polyether ether ketone (PEEK) serves as spine implants, femoral stems, cranial implants, and joint arthroplasty implants due to its mechanical properties resembling the cortical bone, chemical stability, and radiolucency. Although there are standards and antibiotic treatments for infection control during and after surgery, the infection risk is lowered but can not be eliminated. The antibacterial properties of PEEK implants should be improved to provide better infection control. This review includes the strategies for enhancing the antibacterial properties of PEEK in four categories: immobilization of functional materials and functional groups, forming nanocomposites, changing surface topography, and coating with antibacterial material. The measuring methods of antibacterial properties of the current studies of PEEK are explained in detail under quantitative, qualitative, andin vivomethods. The mechanisms of bacterial inhibition by reactive oxygen species generation, contact killing, trap killing, and limited bacterial adhesion on hydrophobic surfaces are explained with corresponding antibacterial compounds or techniques. The prospective analysis of the current studies is done, and dual systems combining osteogenic and antibacterial agents immobilized on the surface of PEEK are found the promising solution for a better implant design.

Synergistic Effect of Nano Strontium Titanate Coating and Ultraviolet C Photofunctionalization on Osteogenic Performance and Soft Tissue Sealing of poly(ether-ether-ketone)

This study aimed to evaluate the bioactivity of poly(ether ether ketone) (PEEK) after surface modification by persistent photoconductive strontium titanate (SrTiO3) magnetron sputtering and ultraviolet (UV) C irradiation. According to the different modifications, the PEEK specimens were randomly divided into five groups (n = 38/group): PEEK, Sr100-PEEK, Sr200-PEEK, UV/PEEK, and UV/Sr200-PEEK. Then, the specimens of Sr100-PEEK and Sr200-PEEK groups were, respectively, coated with 100 and 200 nm thickness photocatalyst SrTiO3 on the PEEK surface by magnetron sputtering. Subsequently, UV-C light photofunctionalized the specimens of PEEK and Sr200-PEEK groups to form UV/PEEK and UV/Sr200-PEEK groups. The specimens were characterized by a step meter, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), and a water contact angle meter. The release test of the Sr ion was performed by inductively coupled plasma mass spectrometry (ICP-MS). In vitro study, osteogenic activity (MC3T3-E1 osteoblast-like cells) and epithelial and connective tissue attachment (gingival epithelial cells GE1 and fibroblasts NIH3T3) were analyzed in five groups. Surface morphology of the specimens was changed after coating, and the Sr content on the Sr-PEEK surface was increased with increasing coating thickness. In addition, the contact angle was increased significantly after magnetron sputtering. After UV-C photofunctionalization, the content of surface elements changed and the contact angle was decreased. The release of Sr ion was sustained, and the final cumulative release amount did not exceed the safety limit. In vitro experiments showed that SrTiO3 improved the cell activity of MC3T3-E1 and UV-C irradiation further enhanced the osteogenic performance of PEEK. Besides, UV-C irradiation also significantly promoted the cell viability, development, and expression of adhesion proteins of GE1 and NIH3T3 on PEEK. The present investigation demonstrated that nano SrTiO3 coating with UV-C photofunctionalization synergistically enhanced the osteogenic properties and soft tissue sealing function of PEEK in vitro.

Ketone Supplementation Dampens Subjective and Objective Responses to Alcohol: Evidence From a Preclinical Rat Study and a Randomized, Cross-Over Trial in Healthy Volunteers

BACKGROUND

Previous preclinical and human studies have shown that a high-fat ketogenic diet and ketone supplements (KS) are efficacious in reducing alcohol craving, alcohol consumption, and signs of alcohol withdrawal. However, the effects of KS on alcohol sensitivity are unknown.

METHODS

In this single-blind, cross-over study, 10 healthy participants (3 females) were administered a single, oral dose of a KS (25 g of ketones from D-β-hydroxybutyric acid and R-1,3-butanediol) or placebo 30 minutes before an oral alcohol dose (0.25 g/kg for women; 0.31 g/kg for men). Assessments of breath alcohol concentration and blood alcohol levels (BAL) and responses on the Drug Effect Questionnaire were repeatedly obtained over 180 minutes after alcohol consumption. In a parallel preclinical study, 8 Wistar rats (4 females) received an oral gavage of KS (0.42 g ketones/kg), water, or the sweetener allulose (0.58 g/kg) followed 15 minutes later by an oral alcohol dose (0.8 g/kg). BAL was monitored for 240 minutes after alcohol exposure.

RESULTS

In humans, the intake of KS before alcohol significantly blunted breath alcohol concentration and BAL, reduced ratings of alcohol liking and wanting more, and increased disliking for alcohol. In rats, KS reduced BAL more than either allulose or water.

CONCLUSION

KS altered physiological and subjective responses to alcohol in both humans and rats, and the effects were likely not mediated by the sweetener allulose present in the KS drink. Therefore, KS could potentially reduce the intoxicating effects of alcohol.

The effect of acute and 14-day exogenous ketone supplementation on glycemic control in adults with type 2 diabetes: two randomized controlled trials

Acute ingestion of the exogenous ketone monoester supplement [(R)-3-hydroxybutyl-(R)-3-hydroxybutyrate] lowers blood glucose, suggesting therapeutic potential in individuals with impaired glucose metabolism. However, it is unknown how acute or repeated ingestion of exogenous ketones affects blood glucose control in individuals with type 2 diabetes (T2D). We conducted two randomized, counterbalanced, double-blind, placebo-controlled crossover trials to determine if 1) acute exogenous ketone monoester (0.3 g/kg body mass; N = 18) or 2) 14-day thrice daily premeal exogenous ketone monoester (15 g; N = 15) supplementation could lower blood glucose in individuals living with T2D. A single dose of the ketone monoester supplement elevated blood β-OHB to ∼2 mM. There were no differences in the primary outcomes of plasma glucose concentration (acutely) or serum fructosamine (glycemic control across 14 days) between conditions. Ketone monoester ingestion acutely increased insulin and lowered nonesterified fatty acid concentrations; plasma metabolomics confirmed a reduction in multiple free fatty acids species and select gluconeogenic amino acids. In contrast, no changes were observed in fasting metabolic outcomes following 14 days of supplementation. In the context of these randomized controlled trials, acute or repeated ketone monoester ingestion in adults with T2D did not lower blood glucose when consumed acutely in a fasted state and did not improve glycemic control following thrice daily premeal ingestion across 14 days. Future studies exploring the mechanistic basis for the (lack of) glucose-lowering effect of exogenous ketone supplementation in T2D and other populations are warranted.NEW & NOTEWORTHY Exogenous ketone supplements can acutely lower blood glucose, suggesting therapeutic potential in individuals with impaired glucose metabolism. However, the effect of exogenous ketones on glucose metabolism in adults with type 2 diabetes has not been investigated in a controlled setting. In adults with type 2 diabetes, ketone monoester ingestion did not lower blood glucose acutely in a fasted state and did not improve glycemic control across thrice daily premeal ingestion across 14 days.

Effect of Acute and Chronic Ingestion of Exogenous Ketone Supplements on Blood Pressure: A Systematic Review and Meta-Analysis

Exogenous ketone supplements have been suggested to have potential cardiovascular benefits, but their overall effect on blood pressure is unclear. Our objective was to perform a systematic review and meta-analysis on the effects of exogenous ketone supplements on blood pressure (BP) and concomitant changes in resting heart rate (HR). Five databases were searched on January 27th, 2023, for randomized and non-randomized studies. A random-effects model meta-analysis was performed including all studies jointly and separately for acute and chronic ingestion of ketone supplements. Out of 4012 studies identified in the search, 4 acute and 6 chronic studies with n = 187 participants were included. Pooled results (n = 10) showed no change in systolic (SMD [95% CI]= -0.14 [-0.40; 0.11]; I2= 30%; p = 0.17) or diastolic BP (-0.12 [-0.30; 0.05]; I2= 0%; p = 0.69), with a potential tendency observed toward increased resting heart rate (0.17 [-0.14; 0.47]; I2= 40%; p = 0.10). Similar results for systolic and diastolic BP were observed when assessing separately the effect of acute and chronic ingestion of ketone supplements (p ≥ 0.33). Supplement dosage was found to modulate the increase in resting heart rate (0.019 ± 0.006; p = 0.013; R2=100%), suggesting that higher supplement doses lead to a higher resting heart rate. Based on currently available data, acute or prolonged ingestion of ketone supplements does not seem to modulate BP. However, a tendency for HR to increase after acute ingestion was observed, particularly with higher doses. Higher quality studies with appropriate standardized measurements are needed to confirm these results.

Cu-Sr Bilayer Bioactive Glass Nanoparticles/Polydopamine Functionalized Polyetheretherketone Enhances Osteogenic Activity and Prevents Implant-Associated Infections through Spatiotemporal Immunomodulation

Key factors contributing to implantation failures include implant-associated infections (IAIs) and insufficient osseointegration of the implants. Polyetheretherketone (PEEK) is widely used in orthopedics, yet its clinical applications are restricted due to its poor osteogenic and antibacterial properties as well as inadequate immune responses. To overcome these drawbacks, a novel spatiotemporal immunomodulation approach is proposed, chelating Cu-Sr bilayer bioactive glass nanoparticles (CS-BGNs) onto the PEEK surface via polydopamine (PDA). The CS-BGNs possess a bilayer core-shell structure where copper is distributed in the outer layer and strontium is clustered in the inner layer. The results show that CS-BGNs/PDA functionalized PEEK demonstrates a controlled and sequential release of Cu2+ and Sr2+ . In the early stage, Cu2+ from the outer layer releases rapidly, while Sr2+ from the inner layer releases in the late stage. This well-ordered release pattern modulates the phenotypic transition of macrophages, which induces M1 polarization in the early stage and M2 polarization in the late stage. Combined with the direct effects of Cu2+ and Sr2+ , the spatiotemporal immunomodulation not only benefits the early antibacterial and tissue-healing process, but also promotes the long-term process of osseointegration, providing new perspectives on the design of novel immunomodulatory biomaterials.

Glucose-primed PEEK orthopedic implants for antibacterial therapy and safeguarding diabetic osseointegration

Diabetic infectious microenvironment (DIME) frequently leads to a critical failure of osseointegration by virtue of its main peculiarities including typical hyperglycemia and pathogenic infection around implants. To address the plaguing issue, we devise a glucose-primed orthopedic implant composed of polyetheretherketone (PEEK), Cu-chelated metal-polyphenol network (hauberk coating) and glucose oxidase (GOx) for boosting diabetic osseointegration. Upon DIME, GOx on implants sostenuto consumes glucose to generate H2O2, and Cu liberated from hauberk coating catalyzes the H2O2 to highly germicidal •OH, which massacres pathogenic bacteria through photo-augmented chemodynamic therapy. Intriguingly, the catalytic efficiency of the coating gets greatly improved with the turnover number (TON) of 0.284 s-1. Moreover, the engineered implants exhibit satisfactory cytocompatibility and facilitate osteogenicity due to the presence of Cu and osteopromotive polydopamine coating. RNA-seq analysis reveals that the implants enable to combat infections and suppress pro-inflammatory phenotype (M1). Besides, in vivo evaluations utilizing infected diabetic rat bone defect models at week 4 and 8 authenticate that the engineered implants considerably elevate osseointegration through pathogen elimination, inflammation dampening and osteogenesis promotion. Altogether, our present study puts forward a conceptually new tactic that arms orthopedic implants with glucose-primed antibacterial and osteogenic capacities for intractable diabetic osseointegration.

Multifunctional modifications of polyetheretherketone implants for bone repair: A comprehensive review

Polyetheretherketone (PEEK) has emerged as a highly promising orthopedic implantation material due to its elastic modulus which is comparable to that of natural bone. This polymer exhibits impressive properties for bone implantation such as corrosion resistance, fatigue resistance, self-lubrication and chemical stability. Significantly, compared to metal-based implants, PEEK implants have mechanical properties that are closer to natural bone, which can mitigate the "stress shielding" effect in bone implantation. Nevertheless, PEEK is incapable of inducing osteogenesis due to its bio-inert molecular structure, thereby hindering the osseointegration process. To optimize the clinical application of PEEK, researchers have been working on promoting its bioactivity and endowing this polymer with beneficial properties, such as antibacterial, anti-inflammatory, anti-tumor, and angiogenesis-promoting capabilities. Considering the significant growth of research on PEEK implants over the past 5 years, this review aims to present a timely update on PEEK's modification methods. By highlighting the latest advancements in PEEK modification, we hope to provide guidance and inspiration for researchers in developing the next generation bone implants and optimizing their clinical applications.

Enhanced osteogenic and antibacterial properties of polyetheretherketone by ultraviolet-initiated grafting polymerization of a gelatin methacryloyl/epsilon-poly-L-lysine/laponite hydrogel coating

Polyetheretherketone (PEEK) is a promising material for use in orthopedic implants, but its bio-inert character and lack of antibacterial activity limit its applications in bone repair. In the present study, considering the advantages of PEEK in self-initiated graft polymerization and of hydrogels in bone tissue engineering, we constructed a hydrogel coating (GPL) consisting of Gelatin methacryloyl (GelMA), methacrylamide-modified ε-poly-l-lysine (ε-PLMA) and Laponite on PEEK through UV-initiated crosslinking. The coating improved the hydrophilicity of PEEK, and the coating degraded slowly so that approximately 80% was retained after incubation in PBS for 8 weeks. In vitro studies revealed that as compared to culturing on PEEK, culturing on PEEK-GPL led to enhanced viability and adhesion of cultured human umbilical cord Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs). Due to the synergistic effect of the micron-scale three-dimensional surface and Laponite, PEEK-GPL exhibited a significantly improved induction of osteogenic differentiation of hWJ-MSCs compared to PEEK, as demonstrated by increased alkaline phosphatase activity, matrix mineralization, and expression of osteogenesis-related genes. Furthermore, PEEK-GPL showed antibacterial activity upon contact with Staphylococcus aureus and Escherichia coli, and this activity would be maintained before complete degradation of the hydrogel because the ε-PLMA was cross-linked covalently into the coating. Thus, PEEK-GPL achieved both osteogenesis and infection prevention in a single simple step, providing a feasible approach for the extensive use of PEEK in bone implants.

The Synthesis of Novel aza-Steroids and α, β-Unsaturated-Cyanoketone from Diosgenin

Recent studies have demonstrated the antiproliferative and cytotoxic effects of aza-steroids and steroidal sapogenins on human cancer cell lines. The scientific community has shown a growing interest in these compounds as drug candidates for cancer treatment. In the current work, we report the synthesis of new diosgenin oxime derivatives as potential antiproliferative agents. From (25 R)-5α-spirost-3,5,6-triol (1), a diosgenin derivative, ketones 2, 3, 4, and 9 were obtained and used as precursors of the new oximes. A condensation reaction was carried out between the steroidal ketones (2, 3, 4, and 9) with hydroxylamine hydrochloride in 2,4,6-trimethylpyridine to produce five spirostanic oximes (four of them are not reported before) with a 42-96% yield. Also, a new spirostanic α, β-unsaturated cyanoketone was synthesized via Beckmann fragmentation using thionyl chloride with a 62% yield. Furthermore, we proposed a reaction mechanism with the aim of explaining such transformation.

Beneficial Effects of Ketone Ester in Patients With Cardiogenic Shock: A Randomized, Controlled, Double-Blind Trial

BACKGROUND

Cardiogenic shock (CS) is a life-threatening condition with sparse treatment options. The ketone body 3-hydroxybutyrate has favorable hemodynamic effects in patients with stable chronic heart failure. Yet, the hemodynamic effects of exogenous ketone ester (KE) in patients with CS remain unknown.

OBJECTIVES

The authors aimed to assess the hemodynamic effects of single-dose enteral treatment with KE in patients with CS.

METHODS

In a double-blind, crossover study, 12 patients with CS were randomized to an enteral bolus of KE and isocaloric, isovolumic placebo containing maltodextrin. Patients were assessed with pulmonary artery catheterization, arterial blood samples, echocardiography, and near-infrared spectroscopy for 3 hours following each intervention separated by a 3-hour washout period.

RESULTS

KE increased circulating 3-hydroxybutyrate (2.9 ± 0.3 mmol/L vs 0.2 ± 0.3 mmol/L, P < 0.001) and was associated with augmented cardiac output (area under the curve of relative change: 61 ± 22 L vs 1 ± 18 L, P = 0.044). Also, KE increased cardiac power output (0.07 W [95% CI: 0.01-0.14]; P = 0.037), mixed venous saturation (3 percentage points [95% CI: 1-5 percentage points]; P = 0.010), and forearm perfusion (3 percentage points [95% CI: 0-6 percentage points]; P = 0.026). Right (P = 0.048) and left (P = 0.017) ventricular filling pressures were reduced whereas heart rate and mean arterial and pulmonary arterial pressures remained similar. Left ventricular ejection fraction improved by 4 percentage points (95% CI: 2-6 percentage points; P = 0.005). Glucose levels decreased by 2.6 mmol/L (95% CI: -5.2 to 0.0; P = 0.047) whereas insulin levels remained unaltered.

CONCLUSIONS

Treatment with KE improved cardiac output, biventricular function, tissue oxygenation, and glycemic control in patients with CS (Treatment With the Ketone Body 3-hydroxybutyrate in Patients With Cardiogenic Shock [KETO-SHOCK1]; NCT04642768).

Polyether ether ketone coated with nanohydroxyapatite/graphene oxide composite promotes bioactivity and antibacterial activity at the surface of the material

Polyether ether ketone (PEEK) is considered an alternative material for manufacturing dental implants. However, PEEK lacks bioactivity and antibacterial action. In a series of experiments designed to enhance the surface properties of PEEK, we present a nanohydroxyapatite (nHA) and graphene oxide (GO) composite as a coating for PEEK-based dental implants to improve biological properties and antibacterial action. PEEK discs were polished, cleaned, and coated with the composite consisting of nHA particles doped with 0.75 wt% graphene oxide by a micro-emulsion technique according to patent US8,206,813. X-ray diffraction, field emission scanning electron microscopy-energy dispersive spectroscopy, and atomic force microscopy were utilized to characterize the composite coating. The wettability of the coated and non-coated samples was assessed by optical contact angle measurement. Antibacterial action of the composite coating was explored against S. aureus and E. coli and cytotoxicity determined utilizing osteoblast-like cells and gingival fibroblasts. The findings showed that the nHA/GO composite coating, approximately 1.3 μm thick, was homogenous with few micro-cracks and adhered to the PEEK surface. The surface roughness was reduced to 21.26 nm and the wettability was improved to 54.6⁰ after coating with the composite coating. Antibacterial activity was moderate, killing 99% of S. aureus and E. coli, with acceptable levels of cytotoxicity to mammalian osteoblast-like cells and gingival fibroblasts.

RGD Peptide-Functionalized Polyether Ether Ketone Surface Improves Biocompatibility and Cell Response

Polyether ether ketone (PEEK) is a biocompatible polymer used in maxillofacial and orthopedic applications because of its mechanical properties and chemical stability. However, this biomaterial is inert and requires surface modification to make it bioactive, enhancing implant-tissue integration and giving the material the ability to interact with the surrounding microenvironment. In this paper, surface of PEEK was activated by oxygen plasma treatment and this resulted in increasing reactivity and surface hydrophilicity. Then, a polydopamine (PDA) coating was deposited over the surface followed by biofunctionalization with an RGD peptide. The plasma effect was studied by contact angle measurements and scanning electron microscopy. X-ray photoelectron spectroscopy confirmed the presence of PDA coating and RGD peptide. Crystallinity and phase identification were carried out through X-ray diffraction. Quantification of the immobilized peptide over the PEEK surface was reached through UV-vis spectroscopy. In addition, in vitro tests with fibroblast cell line (NIH/3T3) determined the viability, attachment, spreading, and proliferation of these cells over the modified PEEK surfaces. According to the results, PEEK surfaces functionalized with peptides demonstrated an increased cellular response with each successive surface modification.

Effect of sulfonation time on physicochemical, osteogenic, antibacterial properties and biocompatibility of carbon fiber reinforced polyether ether ketone

The carbon fiber reinforced polyetheretherketone (CFR-PEEK) has been increasingly used in orthopedics dentistry due to its excellent biocompatibility and mechanical properties. However, the biological inertness and poor antibacterial activity limit its clinical applications. This paper focused on the performances of CFR-PEEK with porous morphology that were exposed to different sulfonation periods (1, 3, 5, and 10 min, corresponding to CP-S1, CP-S3, CP-S5, and CP-S10, respectively). Residual sulfuric acid was removed by acetone rinsing, NaOH immersion, and hydrothermal treatment before in vitro and in vivo studies. The results showed some significant difference in the physicochemical properties, including energy dispersive X-ray spectroscopy (EDS) map of sulfur atoms, X-ray photoelectron spectroscopy (XPS) of valences of sulfur ions, Fourier transformation infrared spectroscopy (FTIR), hydrophilicity, hardness, and elastic modulus among CP-S3, CP-S5, and CP-S10. However, CP-S5 and CP-S10 were more effective in promoting the proliferation, adhesion, and osteogenic differentiation of seeded bone mesenchymal stem cells (BMSCs) and growth inhibition of S. aureus and P. gingivalis compared with other groups. Furthermore, the CP-S5 and CP-S10 samples achieved better cranial bone repair than the non-sulfonation group in a rat model. Therefore, it can be inferred that both 5 and 10 min are viable sulfonation durations for 30% CFR-PEEK. These findings provide a theoretical basis for developing CFR-PEEK for clinical applications.

Ketone ester administration improves glycemia in obese mice

During periods of prolonged fasting/starvation, the liver generates ketones [i.e., β-hydroxybutyrate (βOHB)] that primarily serve as alternative substrates for ATP production. Previous studies have demonstrated that elevations in skeletal muscle ketone oxidation contribute to obesity-related hyperglycemia, whereas inhibition of succinyl CoA:3-ketoacid CoA transferase (SCOT), the rate-limiting enzyme of ketone oxidation, can alleviate obesity-related hyperglycemia. As circulating ketone levels are a key determinant of ketone oxidation rates, we tested the hypothesis that increases in circulating ketone levels would worsen glucose homeostasis secondary to increases in muscle ketone oxidation. Accordingly, male C57BL/6J mice were subjected to high-fat diet-induced obesity, whereas their lean counterparts received a standard chow diet. Lean and obese mice were orally administered either a ketone ester (KE) or placebo, followed by a glucose tolerance test. In tandem, we conducted isolated islet perifusion experiments to quantify insulin secretion in response to ketones. We observed that exogenous KE administration robustly increases circulating βOHB levels, which was associated with an improvement in glucose tolerance only in obese mice. These observations were independent of muscle ketone oxidation, as they were replicated in mice with a skeletal muscle-specific SCOT deficiency. Furthermore, the R-isomer of βOHB produced greater increases in perifusion insulin levels versus the S-isomer in isolated islets from obese mice. Taken together, acute elevations in circulating ketones promote glucose-lowering in obesity. Given that only the R-isomer of βOHB is oxidized, further studies are warranted to delineate the precise role of β-cell ketone oxidation in regulating insulin secretion.NEW & NOTEWORTHY It has been demonstrated that increased skeletal muscle ketone metabolism contributes to obesity-related hyperglycemia. Since increases in ketone supply are key determinants of organ ketone oxidation rates, we determined whether acute elevations in circulating ketones following administration of an oral ketone ester may worsen glucose homeostasis in lean or obese mice. Our work demonstrates the opposite, as acute elevations in circulating ketones improved glucose tolerance in obese mice.

Near-ultraviolet irradiation to stimulate unmodified polyether ether ketone to achieve stable and sustainable antibacterial activity

OBJECTIVES

This study aims to investigate the cytotoxicity and sustainable antibacterial activity of unmodified PEEK under specific wavelength light treatment (365 nm), and its antibacterial mechanism was also preliminarily discussed.

METHODS

A near-ultraviolet source with a wavelength of 365 nm and a power of 5 W were selected. The irradiation time was 30 min, and the distance was 100 mm. A water contact angle tester was used to characterize the surface of the PEEK after 1-15 light treatments. MC3TC-E1 cells were used to evaluate the cytotoxicity of the materials under light treatment. Five kinds of common oral bacteria were detected in vitro, and antibacterial efficiency was determined by colony-forming unit (CFU) and scanning electron microscope (SEM). The antibacterial mechanism of PEEK under light was preliminarily discussed by spectrophotometry. The membrane rupture of Staphylococcus aureus and Escherichia coli was detected by lactate dehydrogenase. Staphylococcus aureus and Staphylococcus mutans were selected for the cyclic antibacterial test. Statistical analysis was performed by one-way analysis of variance and Tukey multiple range test. A significance level of 0.05 was considered (α = 0.05).

RESULTS

The results of the cell experiment showed that PEEK had no cytotoxicity (P > 0.05). CFU results showed that PEEK had an obvious antibacterial effect on Staphylococcus aureus, Staphylococcus mutans, Staphylococcus gordonii and Staphylococcus sanguis, but had no antibacterial effect on Escherichia coli (P < 0.05). The SEM results also verified the above antibacterial effect. The existence of singlet oxygen was confirmed by spectrophotometry. Meanwhile, the rupture of Staphylococcus aureus membrane was verified by lactate dehydrogenase assay. The water contact angle of the PEEK surface did not change significantly after 15 cycles of light treatment. Cyclic antibacterial experiments showed that the antibacterial effect was sustainable.

CONCLUSIONS

This study showed that PEEK has good cytocompatibility with stable and sustainable antibacterial properties under near-ultraviolet. It provides a new idea to solve the non-antibacterial property of PEEK, and also provides a theoretical basis for its further application in dentistry.

Efficient Osteogenic Activity of PEEK Surfaces Achieved by Femtosecond Laser-Hydroxylation

Poly(etheretherketone) (PEEK) is regarded as an attractive orthopedic material because of its good biocompatibility and mechanical properties similar to natural bone. The efficient activation methods for the surfaces of PEEK matrix materials have become a hot research topic. In this study, a method using a femtosecond laser (FSL) followed by hydroxylation was developed to achieve efficient bioactivity. It produces microstructures, amorphous carbon, and grafted -OH groups on the PEEK surface to enhance hydrophilicity and surface energy. Both experimental and simulation results show that our modification leads to a superior ability to induce apatite deposition on the PEEK surface. The results also demonstrate that efficient grafting of C-OH through FSL-hydroxylation can effectively enhance cell proliferation and osteogenic differentiation compared to other modifications, thus improving osteogenic activity. Overall, FSL hydroxylation treatment is proved to be a simple, efficient, and environmentally friendly modification method for PEEK activation. It could expand the applications of PEEK in orthopedics, as well as promote the surface modification and structural design of other polymeric biomaterials to enhance bioactivity.

Are the Cytotoxic Properties of Conjugated Unsaturated Ketones Inactivated by Thiols?

The focus of this study was to examine whether the conversion of cytotoxic conjugated unsaturated ketones (or enones) into the corresponding thiol adducts leads to a reduction or abolition of cytotoxic potencies. A number of enones and related thiol adducts were evaluated against human HCT116 and HT29 colon cancer cells. Some 63% of the IC50 values are less than 10 μM and several compounds are more toxic than 5-FU. The thiol adducts are either more potent or are equipotent with the corresponding enones. A number of compounds are far more toxic to HCT116 and HT29 neoplasms than non-malignant CRL1790 cells leading to impressive Selectivity Index figures. An additional positive feature of these compounds is that they have favorable ADME properties.

Exogenous ketosis elevates circulating erythropoietin and stimulates muscular angiogenesis during endurance training overload

De novo capillarization is a primary muscular adaptation to endurance exercise training and is crucial to improving performance. Excess training load, however, impedes such beneficial adaptations, yet we recently demonstrated that such downregulation may be counteracted by ketone ester ingestion (KE) post-exercise. Therefore, we investigated whether KE could increase pro-angiogenic factors and thereby stimulate muscular angiogenesis during a 3-week endurance training-overload period involving 10 training sessions/week in healthy, male volunteers. Subjects received either 25 g of a ketone ester (KE, n = 9) or a control drink (CON, n = 9) immediately after each training session and before sleep. In KE, but not in CON, the training intervention increased the number of capillary contacts and the capillary-to-fibre perimeter exchange index by 44% and 42%, respectively. Furthermore, KE also substantially increased vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression both at the protein and at the mRNA level. Serum erythropoietin concentration was concomitantly increased by 26%. Conversely, in CON the training intervention increased only the protein content of eNOS. These data indicate that intermittent exogenous ketosis during endurance overload training stimulates muscular angiogenesis. This likely resulted from a direct stimulation of muscle angiogenesis, which may be at least partly due to stimulation of erythropoietin secretion and elevated VEGF activity, and/or an inhibition of the suppressive effect of overload training on the normal angiogenic response to training. This study provides novel evidence to support the potential of exogenous ketosis to benefit endurance training-induced muscular adaptation. KEY POINTS: Increased capillarization is a primary muscular adaptation to endurance exercise training. However, excess training load may impede such response. We previously observed that intermittent exogenous ketosis by post-exercise and pre-sleep ketone ester ingestion (KE) counteracted physiological dysregulations induced by endurance overload training. Therefore, we investigated whether KE could increase pro-angiogenic factors thereby stimulating muscular angiogenesis during a 3-week endurance training overload period. We show that the overload training period in the presence, but not in the absence, of KE markedly increased muscle capillarization (+40%). This increase was accompanied by higher circulating erythropoietin concentration and stimulation of the pro-angiogenic factors vascular endothelial growth factor and endothelial nitric oxide synthase in skeletal muscle. Collectively, our data indicate that intermittent exogenous ketosis may evolve as a potent nutritional strategy to facilitate recovery from strenuous endurance exercise, thereby stimulating beneficial muscular adaptations.

Immune cell response to orthopedic and craniofacial biomaterials depends on biomaterial composition

Materials for craniofacial and orthopedic implants are commonly selected based on mechanical properties and corrosion resistance. The biocompatibility of these materials is typically assessed in vitro using cell lines, but little is known about the response of immune cells to these materials. This study aimed to evaluate the inflammatory and immune cell response to four common orthopedic materials [pure titanium (Ti), titanium alloy (TiAlV), 316L stainless steel (SS), polyetheretherketone (PEEK)]. Following implantation into mice, we found high recruitment of neutrophils, pro-inflammatory macrophages, and CD4+ T cells in response to PEEK and SS implants. Neutrophils produced higher levels of neutrophil elastase, myeloperoxidase, and neutrophil extracellular traps in vitro in response to PEEK and SS than neutrophils on Ti or TiAlV. Macrophages co-cultured on PEEK, SS, or TiAlV increased polarization of T cells towards Th1/Th17 subsets and decreased Th2/Treg polarization compared to Ti substrates. Although SS and PEEK are considered biocompatible materials, both induce a more robust inflammatory response than Ti or Ti alloy characterized by high infiltration of neutrophils and T cells, which may cause fibrous encapsulation of these materials. STATEMENT OF SIGNIFICANCE: Materials for craniofacial and orthopedic implants are commonly selected based on their mechanical properties and corrosion resistance. This study aimed to evaluate the immune cell response to four common orthopedic and craniofacial biomaterials: pure titanium, titanium-aluminum-vanadium alloy, 316L stainless steel, and PEEK. Our results demonstrate that while the biomaterials tested have been shown to be biocompatible and clinically successful, the inflammatory response is largely driven by chemical composition of the biomaterials.

Non-Coding-RNA-Activated Core/Chitosan Shell Nanounits Coated with Polyetheretherketone for Promoting Bone Regeneration and Osseointegration via Osteoimmunology

Bone implant outcome and bone regeneration properties can be improved by the immunomodulation of exosomes (Exos) derived from bone marrow mesenchymal stem cells (BMSCs), which contain cytokines, signaling lipids, and regulatory miRNAs. Analysis of miRNAs in BMSCs-derived exosomes showed that miR-21a-5p exhibited the highest expression and was associated with the NF-κB pathway. Hence, we developed an implant with miR-21a-5p functionality to promote bone incorporation by immunoregulation. Mediated by the potent interaction between tannic acid (TA) and biomacromolecules, the tannic acid modified mesoporous bioactive glass nanoparticles coated with miR-21a-5p (miR-21a-5p@T-MBGNs) were reversibly attached to TA-modified polyetheretherketone (T-PEEK). Cocultured cells could phagocytose miR-21a-5p@T-MBGNs slowly released from miR-21a-5p@T-MBGNs loaded T-PEEK (miMT-PEEK). Moreover, miMT-PEEK boosted macrophage M2 polarization via the NF-κB pathway to increase BMSCs osteogenic differentiation. In vivo testing of miMT-PEEK in the rat air-pouch model and rat femoral drilling model indicated effective macrophage M2 polarization, new bone formation, and excellent osseointegration. Overall, the osteoimmunomodulation of the miR-21a-5p@T-MBGNs-functionalized implant promoted osteogenesis and osseointegration.

Efficacy of Eribulin Plus Gemcitabine Combination in L-Sarcomas

Although the overall survival of advanced soft-tissue sarcoma (STS) patients has increased in recent years, the median progression-free survival is lower than 5 months, meaning that there is an unmet need in this population. Among second-line treatments for advanced STS, eribulin is an anti-microtubule agent that has been approved for liposarcoma. Here, we tested the combination of eribulin with gemcitabine in preclinical models of L-sarcoma. The effect in cell viability was measured by MTS and clonogenic assay. Cell cycle profiling was studied by flow cytometry, while apoptosis was measured by flow cytometry and Western blotting. The activity of eribulin plus gemcitabine was evaluated in in vivo patient-derived xenograft (PDX) models. In L-sarcoma cell lines, eribulin plus gemcitabine showed to be synergistic, increasing the number of hypodiploid events (increased subG1 population) and the accumulation of DNA damage. In in vivo PDX models of L-sarcomas, eribulin combined with gemcitabine was a viable scheme, delaying tumour growth after one cycle of treatment, being more effective in leiomyosarcoma. The combination of eribulin and gemcitabine was synergistic in L-sarcoma cultures and it showed to be active in in vivo studies. This combination deserves further exploration in the clinical context.

Rational design of metabolically stable HDAC inhibitors: An overhaul of trifluoromethyl ketones

Epigenetic regulation of gene expression using histone deacetylase (HDAC) inhibitors is a promising strategy for developing new anticancer agents. The most common HDAC inhibitors are hydroxamates, which, though highly potent, have limitations due to their poor pharmacokinetic properties and lack of isoform selectivity. Trifluoromethylketones (TFMK) developed as alternatives to hydroxamates are rapidly metabolized to inactive trifluoromethyl alcohols in vivo, which prevented their further development as potential drug candidates. In order to overcome this limitation, we designed trifluoropyruvamides (TFPAs) as TFMK surrogates. The presence of an additional electron withdrawing group next to the ketone carbonyl group made the hydrate form of the ketone more stable, thus preventing its metabolic reduction to alcohol in vivo. In addition, this structural modification reduces the potential of the TFMK group to act as a covalent warhead to eliminate off-target effects. Additional structural changes in the cap group of the inhibitors gave analogues with IC50 values ranging from upper nanomolar to low micromolar in the cytotoxicity assay, and they were more selective for cancer cells over normal cells. Some of the most active analogues inhibited HDAC enzymes with low nanomolar IC50 values and were found to be more selective for HDAC8 over other isoforms. These molecules provide a new class of HDAC inhibitors with a metabolically stable metal-binding group that could be used to develop selective HDAC inhibitors by further structural modification.

Dual-Functional Polyetheretherketone Surface with an Enhanced Osteogenic Capability and an Antibacterial Adhesion Property In Vitro by Chitosan Modification

A chitosan layer was covalently bonded to a polyetheretherketone (PEEK) surface using a simple facile self-assembly method to address inadequate biological activity and infection around the implant. The surface characterization, layer degradation, biological activity, and antibacterial adhesion properties of chitosan-modified PEEK (PEEK-CS) were studied. Through chitosan grafting, the surface morphology changed, the surface roughness increased, and the contact angle decreased significantly. PEEK-CS boosted cell adhesion, proliferation, increased alkaline phosphate activity, extracellular matrix mineralization, and expression of osteogenic genes. PEEK-CS demonstrated less adhesion to Porphyromonas gingivalis as well as less bacterial adhesion to P. gingivalis and Streptococcus mutans. According to our findings, chitosan modification significantly improved the osteogenic ability and antibacterial adhesion of PEEK in vitro.

Strontium-modified porous polyetheretherketone with the triple function of osteogenesis, angiogenesis, and anti-inflammatory for bone grafting

Polyetheretherketone (PEEK) is a potential bone repair material because of its stable chemical and good mechanical properties. However, the biological inertness of PEEK limits its clinical application. Sr²⁺ has multi biological functions, including promoting bone formation and blood vessel regeneration and inhibiting inflammation. In this paper, PEEK was modified with Sr²⁺ with the purpose to construct PEEK bone graft material with triple functions of osteogenesis, angiogenesis, and anti-inflammatory. The results showed that Sr-modified PEEK could stably release Sr²⁺ for a long time in the PBS solution, and indeed could promote the proliferation and differentiation of osteoblasts, promote angiogenesis, and inhibit inflammation. Therefore, it is believed that this multifunctional PEEK with Sr²⁺ should show great promise for clinical applications in bone repair.

Decorated Polyetheretherketone Implants with Antibacterial and Antioxidative Effects through Layer-by-Layer Nanoarchitectonics Facilitate Diabetic Bone Integration with Infection

Patients suffering diabetic bone defects still need some new and effective strategies to achieve enhanced prognostic effects. Although medical implants are the common treatment of bone defects, the excessive oxidative stress and high risk of bacterial infection in diabetes mellitus lead to a higher risk of implant failure. To improve the healing ability of diabetic bone defects, herein, polyetheretherketone (PEEK) was modified through a developed layer-by-layer (LBL) construction strategy to obtain multifunctional PEEK (SP@(TA-GS/PF)*3) by the assembly of tannic acid (TA), gentamicin sulfate (GS) and Pluronic F127 (PF127) on the basis of prepared porous PEEK through sulfonation (SPEEK). The prepared SP@(TA-GS/PF)*3 exhibited sustained antimicrobial activity and enhanced the differentiation of osteoblast (MC3T3-E1) for needed osteogenesis. Moreover, SP@(TA-GS/PF)*3 scavenged excessive oxidative stress to promote the growth of H₂O₂ damaged HUVEC with enhanced secretion of VEGF for neovascularization. In addition, the remarkable in vivo outcomes of angiogenesis and osseointegration were revealed by the subcutaneous implant model and bone tissue implant model in diabetic rats, respectively. The in vitro and in vivo results demonstrated that modified PEEK with multifunction can be an attractive tool for enhancing bone integration under diabetic conditions, underpinning the clinical application potential of modified implants for diabetic osseointegration.

Selective Polyetheretherketone Implants Combined with Graphene Cause Definitive Cell Adhesion and Osteogenic Differentiation

INTRODUCTION

Polyetheretherketone (PEEK) has good biosafety and chemical stability for bone repair. However, PEEK is biologically inert and cannot promote bone apposition. This study investigated whether graphene-modified PEEK (G-PEEK) could improve cell adhesion and osteogenic differentiation.

METHODS

G-PEEK was prepared by melted blending and was characterized. In vitro, the biocompatibility of G-PPEK and the ability to promote cell adhesion and osteogenic differentiation in rabbit bone marrow mesenchymal stem cells (rBMSCs) were examined using live and dead cell double staining, the cell counting kit-8 (CCK-8) assay, immunofluorescence and quantitative real-time PCR (qRT‒PCR). An in vivo rabbit extra-articular graft-to-bone healing model was established. At 4 and 12 weeks after surgery, CT analysis and histological evaluation were performed.

RESULTS

In vitro, G-PEEK significantly improved the adhesion and proliferation of rBMSCs, with good biocompatibility. In vivo, G-PEEK promoted new bone formation at the site of the bone defect.

CONCLUSION

G-PEEK showed excellent osteogenesis performance, which promises new applications in implant materials.

Insight into the impacts and mechanisms of ketone stress on the antibiotic resistance in Escherichia coli

Accumulation of toxic organic has posed a substantial pressure on the proliferation of bacterial resistance. While aromatic organics have been demonstrated to enhance the antibiotic resistance in bacteria, no information is yet available on the effects of non-aromatic organics on the variations of bacterial resistance. Here, we investigated the effects of a typical ketone (i.e., methylisobutanone (MIBK)) on the variations of antibiotic resistance in Escherichia coli (E. coli). The results showed that the growth of resistant E. coli under environmental concentration of 50 μg/L MIBK was firstly inhibited as explained by the transient disruption in the cell membrane and then recovered possibly due to the reactive oxygen species. Exposure to 50 μg/L MIBK gradually raised the abundance of representative resistance gene (ampR) in E. coli. In contrast, the high concentration of 50 mg/L MIBK continuously inhibited the growth of resistant E. coli by disrupting cell membrane and notably promoted the proliferation of ampR through enhancing the horizontal transformation and up-regulating the expression of efflux pump gene. These findings provided the first evidence for the evolution of bacterial resistance in response to ketone organics.

Bioheterojunction-Engineered Polyetheretherketone Implants With Diabetic Infectious Micromilieu Twin-Engine Powered Disinfection for Boosted Osteogenicity

Diabetic infectious micromilieu (DIM) leads to a critical failure rate of osseointegration by virtue of two main peculiarities: high levels of topical glucose and inevitable infection. To tackle the daunting issue, a bioheterojunction-engineered orthopedic polyetheretherketone (PEEK) implant consisting of copper sulfide/graphene oxide (CuS/GO) bioheterojunctions (bioHJs) and glucose oxidase (GOx) is conceived and developed for DIM enhanced disinfection and boosted osseointegration. Under hyperglycemic micromilieu, GOx can convert surrounding glucose into hydrogen peroxide (H₂ O₂ ). Then, upon infectious micromilieu, the bioHJs enable the catalyzation of H₂ O₂ to highly germicidal hydroxyl radical (·OH). As a result, the engineered implants massacre pathogenic bacteria through DIM twin-engine powered photo-chemodynamic therapy in vitro and in vivo. In addition, the engineered implants considerably facilitate cell viability and osteogenic activity of osteoblasts under a hyperglycemic microenvironment via synergistic induction of copper ions (Cu²⁺ ) and GO. In vivo studies using bone defect models of diabetic rats at 4 and 8 weeks further authenticate that bioHJ-engineering PEEK implants substantially elevate their osseointegration through biofilm elimination and vascularization, as well as macrophage reprogramming. Altogether, the present study puts forward a tactic that arms orthopedic implants with DIM twin-engine powered antibacterial and formidable osteogenic capacities for diabetic stalled osseointegration.

Exogenous glucose oxidation during endurance exercise under low energy availability

The present study was conducted to determine the effect of endurance exercise under low energy availability (EA) on exogenous glucose oxidation during endurance exercise. Ten active males (21.4 ± 0.6 years, 170.4 ± 1.4 cm, 62.4 ± 1.5 kg, 21.5 ± 0.4 kg/m²) completed two trials, consisting of two consecutive days (days 1 and 2) of endurance training under low EA (19.9 ± 0.2 kcal/kg fat free mass [FFM]/day, LEA trial) or normal EA (46.4 ± 0.1 kcal/kg FFM/day, NEA trial). The order of these two trials was randomized with at least a 1-week interval between trials. As an endurance training, participants performed 60 min of treadmill running at 70% of maximal oxygen uptake (V˙O2max) during two consecutive days (on days 1 and 2). On day 1, the endurance training was performed with consumed individually manipulated meals. During the endurance exercise on day 2, exogenous glucose oxidation was evaluated using ¹³C-labeled glucose, and respiratory gas samples were collected. In addition, blood glucose and lactate concentrations were measured immediately after exercise on day 2. Body composition, blood parameters, and resting respiratory gas variables were evaluated under overnight fasting on days 1 and 2. Body weight was significantly reduced in the LEA trial on day2 (day1: 61.8 ± 1.4 kg, day 2: 61.3 ± 1.4 kg, P < 0.001). There were no significant differences between trials in ¹³C excretion (P = 0.33) and area under the curve during the 60 min of exercise (LEA trial: 40.4 ± 3.1 mmol•60min, NEA trial: 40.4 ± 3.1 mmol•60min, P = 0.99). However, the respiratory exchange ratio (RER, LEA trial: 0.88 ± 0.01, NEA trial: 0.90 ± 0.01) and carbohydrate oxidation (LEA trial: 120.1 ± 8.8 g, NEA trial: 136.8 ± 8.6 g) during endurance exercise showed significantly lower values in the LEA trial than in the NEA trial (P = 0.01 for RER and carbohydrate oxidation). Serum insulin and total ketone body concentrations were significantly changed after a day of endurance training under low EA (P = 0.04 for insulin, P < 0.01 for total ketone). In conclusion, low EA during endurance exercise reduced systemic carbohydrate oxidation; however, exogenous glucose oxidation (evaluated by ¹³C excretion) remained unchanged during exercise under low EA.

2-Deoxy-D-glucose Alleviates Cancer Cachexia-Induced Muscle Wasting by Enhancing Ketone Metabolism and Inhibiting the Cori Cycle

Cachexia is characterized by progressive weight loss accompanied by the loss of specific skeletal muscle and adipose tissue. Increased lactate production, either due to the Warburg effect from tumors or accelerated glycolysis effects from cachectic muscle, is the most dangerous factor for cancer cachexia. This study aimed to explore the efficiency of 2-deoxy-D-glucose (2-DG) in blocking Cori cycle activity and its therapeutic effect on cachexia-associated muscle wasting. A C26 adenocarcinoma xenograft model was used to study cancer cachectic metabolic derangements. Tumor-free lean mass, hindlimb muscle morphology, and fiber-type composition were measured after in vivo 2-DG administration. Activation of the ubiquitin-dependent proteasome pathway (UPS) and autophagic–lysosomal pathway (ALP) was further assessed. The cachectic skeletal muscles of tumor-bearing mice exhibited altered glucose and lipid metabolism, decreased carbohydrate utilization, and increased lipid β-oxidation. Significantly increased gluconeogenesis and decreased ketogenesis were observed in cachectic mouse livers. 2-DG significantly ameliorated cancer cachexia-associated muscle wasting and decreased cachectic-associated lean mass levels and fiber cross-sectional areas. 2-DG inhibited protein degradation-associated UPS and ALP, increased ketogenesis in the liver, and promoted ketone metabolism in skeletal muscle, thus enhancing mitochondrial bioenergetic capacity. 2-DG effectively prevents muscle wasting by increasing ATP synthesis efficiency via the ketone metabolic pathway and blocking the abnormal Cori cycle.

Human osteoblasts response to different dental implant abutment materials: An in-vitro study

OBJECTIVES

This study aimed to investigate human osteoblasts (HOB) response towards different dental implant abutment materials.

METHODS

Five dental implant abutment materials were investigated: (1) titanium (Ti), (2) titanium coated nitride (TiN), (3) cobalt chromium (CoCr), (4) zirconia (ZrO₂), and (5) modified polyether ether ketone (m-PEEK). HOBs were cultured, expanded, and seeded according to the supplier's protocol (PromoCell, UK). Cell proliferation and cytotoxicity were evaluated at days 1, 3, 5, and 10 using Alamar Blue (alamarBlue) and lactate dehydrogenase (LDH) colorimetric assays. Data were analysed via two-way ANOVA, one-way ANOVA and Tukey's post hoc test (significance was determined as p < 0.05 for all tests).

RESULTS

All the investigated materials showed high and comparable initial proliferation activities apart from ZrO₂ (46.92%), with P% of 79.91%, 68.77%, 73.20%, and 65.46% for Ti, TiN, CoCr, and m-PEEK, respectively. At day 10, all materials exhibited comparable and lower P% than day 1 apart from TiN (70.90%) with P% of 30.22%, 40.64%, 37.27%, and 50.65% for Ti, CoCr, ZrO₂, and m-PEEK, respectively. The cytotoxic effect of the investigated materials was generally low throughout the whole experiment. At day 10, the cytotoxicity % was 7.63%, 0.21%, 13.30%, 5.32%, 8.60% for Ti, TiN, CoCr, ZrO₂, and m-PEEK. The Two-way ANOVA and Tukey's Multiple Comparison Method highlighted significant material and time effects on cell proliferation and cytotoxicity, and a significant interaction (p < 0.0001) between the tested materials. Notably, TiN and m-PEEK showed improved HOB proliferation activity and cytotoxic levels than the other investigated materials. In addition, a non-significant negative correlation between viability and cytotoxicity was found for all tested materials. Ti (p = 0.07), TiN (p = 0.28), CoCr (p = 0.15), ZrO₂ (p = 0.17), and m-PEEK (p = 0.12).

SIGNIFICANCE

All the investigated materials showed excellent biocompatibility properties with more promising results for the newly introduced TiN and m-PEEK as alternatives to the traditionally used dental implant and abutment materials.

Benzobicyclic ketones, cycloheptenone oxide derivatives, guaiane-type sesquiterpenes, and alkaloids isolated from Taraxacum mongolicum Hand.-Mazz

Ten previously undescribed compounds, including two benzobicyclic ketones, one cycloheptenone oxide derivative, three guaiane-type sesquiterpenes, and four alkaloids, along with one known cycloheptenone oxide derivative, were isolated from the whole plants of Taraxacum mongolicum Hand.-Mazz. Their structures were elucidated by UV, IR, HR-ESI-MS, 1D and 2D NMR spectroscopy, ECD spectroscopy, or X-ray diffraction analysis. Notably, benzobicyclic ketones have never been isolated from nature before. The 70% EtOH-H₂O extract of T. mongolicum displayed a significant inhibitory activity (33%) against croton oil-induced mouse ear edema. The two cycloheptenone oxide derivatives exhibited anti-inflammatory activities at 10 μM and significantly reduced the nitric oxide (NO) and interleukin-6 (IL-6) levels in RAW 264.7 macrophages induced by lipopolysaccharide (LPS), with inhibitory rates of 26.4-64.4%.

Peek dental implants coated with boron-doped nano-hydroxyapatites: Investigation of in-vitro osteogenic activity

BACKGROUND

PEEK is a high-performance thermoplastic that has many potential uses in orthopaedics and dentistry, and it has been shown to be a substitute for titanium (Ti) implants. However, PEEK is an inherently inert material, and that characteristic limits its cellular adhesion and bone integration. The aim of this study is to determine a suitable surface modification method for increasing the osteogenic potential of polyetheretherketone (PEEK) implants used in periodontal applications.

METHODS

In this work, a nanostructured porous surface is created on PEEK material by sulfonation, in sulfuric acid at room temperature for 20 min, and thus SPEEK samples were obtained. Then, PEEK and SPEEK samples were coated with boron (B) doped hydroxyapatite (HAp) nanoparticles (B-nHAp) precipitated from concentrated synthetic body fluid (10xSBF) by a microwave-assisted method conducted at 600 W. In vitro cell culture studies were carried out with periodontal ligament cells (PDL) on the samples. Osteogenic differentiation of PDL cells on PEEK, SPEEK and SPEEK-B-nHAp was evaluated using ALP activity assay, hydroxyproline assay, and RT-qPCR.

RESULTS

In vitro cell culture studies disclosed improved adhesion and proliferation of PDL cells on the SPEEK and B-nHAp coated SPEEK surfaces (SPEEK-B-nHAp). Results of these assays confirmed that treated PEEK surfaces, especially SPEEK-B-nHAp, significantly enhanced osteogenic differentiation of PDL cells in vitro compared with untreated PEEK surfaces.

CONCLUSION

Here a simple, easy to-use, and efficient modification method based on the properties of boron is proposed for increasing osteogenic potential of PEEK implants.

Nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants enhances autophagic clearance in Pompe disease

Alglucosidase alpha is an orphan drug approved for enzyme replacement therapy (ERT) in Pompe disease (PD); however, its efficacy is limited in skeletal muscle because of a partial blockage of autophagic flux that hinders intracellular trafficking and enzyme delivery. Adjunctive therapies that enhance autophagic flux and protect mitochondrial integrity may alleviate autophagic blockage and oxidative stress and thereby improve ERT efficacy in PD. In this study, we compared the benefits of ERT combined with a ketogenic diet (ERT-KETO), daily administration of an oral ketone precursor (1,3-butanediol; ERT-BD), a multi-ingredient antioxidant diet (ERT-MITO; CoQ10, α-lipoic acid, vitamin E, beetroot extract, HMB, creatine, and citrulline), or co-therapy with the ketone precursor and multi-ingredient antioxidants (ERT-BD-MITO) on skeletal muscle pathology in GAA-KO mice. We found that two months of 1,3-BD administration raised circulatory ketone levels to ≥1.2 mM, attenuated autophagic buildup in type 2 muscle fibers, and preserved muscle strength and function in ERT-treated GAA-KO mice. Collectively, ERT-BD was more effective vs. standard ERT and ERT-KETO in terms of autophagic clearance, dampening of oxidative stress, and muscle maintenance. However, the addition of multi-ingredient antioxidants (ERT-BD-MITO) provided the most consistent benefits across all outcome measures and normalized mitochondrial protein expression in GAA-KO mice. We therefore conclude that nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants may provide an alternative to ketogenic diets for inducing ketosis and enhancing autophagic flux in PD patients.

2-undecanone protects against fine particles-induced heart inflammation via modulating Nrf2/HO-1 and NF-κB pathways

Exposure to air pollution has been closely associated with some cardiovascular disease. One of the mechanisms of PM_2.5 -mediated heart injury may be to promote inflammation. We aim to investigate whether the main extract of Houttuynia cordata, 2-undecanone, can prevent the inflammation caused by PM_2.5 , and to reveal the underlying mechanisms. The results showed that PM_2.5 increased the expression of certain inflammatory cytokines, and caused oxidative damage in BALB/c mice and H9C2 cells. Supplementation with 2-undecanone attenuated this PM_2.5 -induced inflammatory injury and oxidative damage. Further, we elucidated that the protective effect of 2-undecanone may be associated with NF-κB and Nrf2/HO-1 pathways. The NF-κB pathway was distinctly activated after treated by PM_2.5 , which can be blocked by 2-undecanone, accompanied by increasing Nrf2 and HO-1 levels. To figure out the relationship between NF-κB and Nrf2/HO-1 pathways, we knocked down Nrf2 gene. NF-κB pathway proteins and downstream inflammatory cytokines were significantly increased after treatment with PM_2.5 , while 2-undecanone could decrease expression of these proteins. In conclusion, it is possible that 2-undecanone can induce the expression of the antioxidant enzyme HO-1 by activating Nrf2, thereby reducing NF-κB pathway and inflammatory damage of mouse myocardium caused by PM_2.5 exposure.

Survey on the Recent Advances in 4-Hydroxyphenylpyruvate Dioxygenase (HPPD) Inhibition by Diketone and Triketone Derivatives and Congeneric Compounds: Structural Analysis of HPPD/Inhibitor Complexes and Structure-Activity Relationship Considerations

The serendipitous discovery of the HPPD inhibitors from allelopathic plants opened the way for searching new and effective herbicidal agents by application of classical hit-to-lead optimization approaches. A plethora of active and selective compounds were discovered that belong to three major classes of cyclohexane-based triketones, pyrazole-based diketones, and diketonitriles. In addition, to enhance inhibitory constant and herbicidal activity, many efforts were also made to gain broader weed control, crop safety, and eventual agricultural applicability. Moreover, HPPD inhibitors emerged as therapeutic agents for inherited and metabolic human diseases as well as vector-selective insecticides in the control of hematophagous arthropods. Given the large set of experimental data available, structure-activity relationship analysis could be used to derive suggestions for next generation optimized compounds.

Bioinspired Surface Functionalization of Poly(ether ether ketone) for Enhancing Osteogenesis and Bacterial Resistance

In orthopedics, developing functionalized biomaterials to enhance osteogenesis and bacterial resistance is crucial. Although poly(ether ether ketone) (PEEK) is regarded as an important engineering plastic for biomedical material with excellent mechanical properties and biocompatibility, its biological inertness has greatly compromised its application in biomedical engineering. Inspired by the catecholamine chemistry of mussels, we propose a universal and versatile approach for enhancing the osteogenesis and antibacterial performances of PEEK based on surface functionalization of polydopamine-modified nanohydroxyapatite and lysozyme simultaneously. The characterizations of surface morphology and elemental composition revealed that the composite coating was successfully added to the PEEK surface. Additionally, the in vitro cell experiment and biomineralization assay indicated that the composite coating-modified PEEK was biocompatible with significantly improved bioactivity to promote osteogenesis and biomineralization compared with the untreated PEEK. Furthermore, the antibacterial test demonstrated that the composite coating had a strongly destructive effect on two bacteria (Staphylococcus aureus and Escherichia coli) with antibacterial ratios of 98.7% and 96.1%, respectively. In summary, the bioinspired method for surface functionalization can enhance the osteogenesis and bacterial resistance of biomedical materials, which may represent a potential approach for designing functionalized implants in orthopedics.

In vivo Structure-Activity Relationship of Dihydromethysticin in Reducing Nicotine-Derived Nitrosamine Ketone (NNK)-Induced Lung DNA Damage against Lung Carcinogenesis in A/J Mice

Lung cancer is the leading cause of cancer-related deaths and chemoprevention should be developed. We recently identified dihydromethysticin (DHM) as a promising candidate to prevent NNK-induced lung tumorigenesis. To probe its mechanisms and facilitate its future translation, we investigated the structure-activity relationship of DHM on NNK-induced DNA damage in A/J mice. Twenty DHM analogs were designed and synthesized. Their activity in reducing NNK-induced DNA damage in the target lung tissues was evaluated. The unnatural enantiomer of DHM was identified to be more potent than the natural enantiomer. The methylenedioxy functional moiety did not tolerate modifications while the other functional groups (the lactone ring and the ethyl linker) accommodated various modifications. Importantly, analogs of high structural similarity to DHM with distinct efficacy in reducing NNK-induced DNA damage have been identified. They will serve as chemical probes to elucidate the mechanisms of DHM in blocking NNK-induced lung carcinogenesis.

Mesh Ti6Al4V Material Manufactured by Selective Laser Melting (SLM) as a Promising Intervertebral Fusion Cage

Intervertebral cages made of Ti6Al4V alloy show excellent osteoconductivity, but also higher stiffness, compared to commonly used polyether-ether-ketone (PEEK) materials, that may lead to a stress-shielding effect and implant subsidence. In this study, a metallic intervertebral fusion cage, with improved mechanical behavior, was manufactured by the introduction of a three-dimensional (3D) mesh structure to Ti6Al4V material, using an additive manufacturing method. Then, the mechanical and biological properties of the following were compared: (1) PEEK, with a solid structure, (2) 3D-printed Ti6Al4V, with a solid structure, and (3) 3D-printed Ti6Al4V, with a mesh structure. A load-induced subsidence test demonstrated that the 3D-printed mesh Ti6Al4V cage had significantly lower tendency (by 15%) to subside compared to the PEEK implant. Biological assessment of the samples proved that all tested materials were biocompatible. However, both titanium samples (solid and mesh) were characterized by significantly higher bioactivity, osteoconductivity, and mineralization ability, compared to PEEK. Moreover, osteoblasts revealed stronger adhesion to the surface of the Ti6Al4V samples compared to PEEK material. Thus, it was clearly shown that the 3D-printed mesh Ti6Al4V cage possesses all the features for optimal spinal implant, since it carries low risk of implant subsidence and provides good osseointegration at the bone-implant interface.

Peptidomimetic α-Acyloxymethylketone Warheads with Six-Membered Lactam P1 Glutamine Mimic: SARS-CoV-2 3CL Protease Inhibition, Coronavirus Antiviral Activity, and in Vitro Biological Stability

Recurring coronavirus outbreaks, such as the current COVID-19 pandemic, establish a necessity to develop direct-acting antivirals that can be readily administered and are active against a broad spectrum of coronaviruses. Described in this Article are novel α-acyloxymethylketone warhead peptidomimetic compounds with a six-membered lactam glutamine mimic in P1. Compounds with potent SARS-CoV-2 3CL protease and in vitro viral replication inhibition were identified with low cytotoxicity and good plasma and glutathione stability. Compounds 15e, 15h, and 15l displayed selectivity for SARS-CoV-2 3CL protease over CatB and CatS and superior in vitro SARS-CoV-2 antiviral replication inhibition compared with the reported peptidomimetic inhibitors with other warheads. The cocrystallization of 15l with SARS-CoV-2 3CL protease confirmed the formation of a covalent adduct. α-Acyloxymethylketone compounds also exhibited antiviral activity against an alphacoronavirus and non-SARS betacoronavirus strains with similar potency and a better selectivity index than remdesivir. These findings demonstrate the potential of the substituted heteroaromatic and aliphatic α-acyloxymethylketone warheads as coronavirus inhibitors, and the described results provide a basis for further optimization.

Structure-Based Optimization of ML300-Derived, Noncovalent Inhibitors Targeting the Severe Acute Respiratory Syndrome Coronavirus 3CL Protease (SARS-CoV-2 3CLpro)

Starting from the MLPCN probe compound ML300, a structure-based optimization campaign was initiated against the recent severe acute respiratory syndrome coronavirus (SARS-CoV-2) main protease (3CLpro). X-ray structures of SARS-CoV-1 and SARS-CoV-2 3CLpro enzymes in complex with multiple ML300-based inhibitors, including the original probe ML300, were obtained and proved instrumental in guiding chemistry toward probe compound 41 (CCF0058981). The disclosed inhibitors utilize a noncovalent mode of action and complex in a noncanonical binding mode not observed by peptidic 3CLpro inhibitors. In vitro DMPK profiling highlights key areas where further optimization in the series is required to obtain useful in vivo probes. Antiviral activity was established using a SARS-CoV-2-infected Vero E6 cell viability assay and a plaque formation assay. Compound 41 demonstrates nanomolar activity in these respective assays, comparable in potency to remdesivir. These findings have implications for antiviral development to combat current and future SARS-like zoonotic coronavirus outbreaks.