Functionally graded hydrogels with opposing biochemical cues for osteochondral tissue engineering.

Osteochondral tissue (OC) repair remains a significant challenge in the field of musculoskeletal tissue engineering. OC tissue displays a gradient structure characterised by variations in both cell types and extracellular matrix components from cartilage to the subchondral bone. These functional gradients in the native tissue have been replicated to engineer osteochondral tissue in vitro. While diverse fabrication methods have been employed to create these microenvironments, emulating the natural gradients and effective regeneration of the tissue continues to present a significant challenge. In this study, we present the design and development of an interpenetrating (IPN) hydrogel with opposing dual biochemical gradients with the aim of regenerating the complete osteochondral unit. The gradients of biochemical cues were generated using an in-house built extrusion system in CMC-Silk IPN hydrogel having improved mechanical strength. Firstly, we fabricated a hydrogel that exhibits a smooth transition of sCMC and TGF-ß1 (SCT gradient hydrogel) from the upper to the lower region of the IPN hydrogel, with the intent of regenerating the cartilage layer. Secondly, a hydrogel with a HAp gradient (HAp gradient hydrogel) from the lower to the upper region was fabricated to facilitate the regeneration of the subchondral bone layer. Subsequently, we developed a dual biochemical gradient hydrogel with the goal of regenerating the entire osteochondral unit. The fabricated hydrogel demonstrated a smooth transition of sCMC + TGF-ß1 and HAp gradients in opposing directions, along with a blend of both the biochemical cues at the interface. The results showed that the hydrogels having biochemical cues corresponding to the three zones (i.e., cartilage, interface and bone) of dual biochemical gradient hydrogel led to differentiation of BMSCs towards their respective lineages, thereby demonstrating their efficacy in directing the fate of progenitor cells. The developed dual gradient hydrogel provided biochemical signals that have the potential to facilitate tissue growth and regeneration of the entire osteochondral tissue with a smooth transition from cartilage (soft) to bone (hard) tissues. In summary, our study provides a simple and innovative method for incorporating biochemical cues into hydrogels. This promising approach is translatable and has the potential to be extrapolated to other interface tissues. .

A Novel Digital Health Platform With Health Coaches to Optimize Surgical Patients: Feasibility Study at a Large Academic Health System.

BACKGROUND: Pip is a novel digital health platform (DHP) that combines human health coaches (HCs) and technology with patient-facing content. This combination has not been studied in perioperative surgical optimization. OBJECTIVE: This study's aim was to test the feasibility of the Pip platform for deploying perioperative, digital, patient-facing optimization guidelines to elective surgical patients, assisted by an HC, at predefined intervals in the perioperative journey. METHODS: We conducted an institutional review board-approved, descriptive, prospective feasibility study of patients scheduled for elective surgery and invited to enroll in Pip from 2.5 to 4 weeks preoperatively through 4 weeks postoperatively at an academic medical center between November 22, 2022, and March 27, 2023. Descriptive primary end points were patient-reported outcomes, including patient satisfaction and engagement, and Pip HC evaluations. Secondary end points included mean or median length of stay (LOS), readmission at 7 and 30 days, and emergency department use within 30 days. Secondary end points were compared between patients who received Pip versus patients who did not receive Pip using stabilized inverse probability of treatment weighting. RESULTS: A total of 283 patients were invited, of whom 172 (60.8%) enrolled in Pip. Of these, 80.2% (138/172) patients had ≥1 HC session and proceeded to surgery, and 70.3% (97/138) of the enrolled patients engaged with Pip postoperatively. The mean engagement began 27 days before surgery. Pip demonstrated an 82% weekly engagement rate with HCs. Patients attended an average of 6.7 HC sessions. Of those patients that completed surveys (95/138, 68.8%), high satisfaction scores were recorded (mean 4.8/5; n=95). Patients strongly agreed that HCs helped them throughout the perioperative process (mean 4.97/5; n=33). The average net promoter score was 9.7 out of 10. A total of 268 patients in the non-Pip group and 128 patients in the Pip group had appropriate overlapping distributions of stabilized inverse probability of treatment weighting for the analytic sample. The Pip cohort was associated with LOS reduction when compared to the non-Pip cohort (mean 2.4 vs 3.1 days; median 1.9, IQR 1.0-3.1 vs median 3.0, IQR 1.1-3.9 days; mean ratio 0.76; 95% CI 0.62-0.93; P=.009). The Pip cohort experienced a 49% lower risk of 7-day readmission (relative risk [RR] 0.51, 95% CI 0.11-2.31; P=.38) and a 17% lower risk of 30-day readmission (RR 0.83, 95% CI 0.30-2.31; P=.73), though these did not reach statistical significance. Both cohorts had similar 30-day emergency department returns (RR 1.06, 95% CI 0.56-2.01, P=.85). CONCLUSIONS: Pip is a novel mobile DHP combining human HCs and perioperative optimization content that is feasible to engage patients in their perioperative journey and is associated with reduced hospital LOS. Further studies assessing the impact on clinical and patient-reported outcomes from the use of Pip or similar DHPs HC combinations during the perioperative journey are required.

Extra-Corporeal Membrane Oxygenation in Pregnancy.

Extracorporeal membrane oxygenation (ECMO) is a cardiac or pulmonary function support system that is used in cases of refractory organ failure in addition to conventional treatment. Currently, Level I evidence is not yet available, which reflects improved outcomes with ECMO in pregnant women, the use in pregnancy should be indicated in selected cases and only in specialized centers. We searched articles in the most important scientific databases from 2009 until 31 December 2023 consulting also the site ClinicalTrials.com to find out about studies that have been recently conducted or are currently ongoing. We matched the combination of the following keywords: "ECMO and pregnancy", "H1N1 and pregnancy", "COVID-19 and pregnancy", "ARDS and pregnancy", "ECMO and pregnancy AND (cardiac arrest)". We selected the following number of articles for each keyword combination: "ECMO and pregnancy" (665 articles); "ECMO and influenza H1N1" (384 articles); "pregnancy and influenza H1N1" (1006 articles); "pregnancy and ARDS" (2930 articles); "ECMO and pregnancy and ARDS and influenza H1N1" (24 articles); and "[ECMO and pregnancy AND (cardiac arrest)]" (74 articles). After careful inspection, only 43 papers fitted our scope. There are two types of ECMO: venous-venous (VV-ECMO) and venous-arterial (VA-ECMO). The first-one is necessary to cope with severe hypoxia: oxygen-depleted blood is taken from the venous circulation, oxygenated, and carbon dioxide removed from the extracorporeal circuit and returned to the same venous system. The VA-ECMO is a type of mechanical assistance to the circulatory system that allows to put the failing organ at rest by ensuring adequate oxygenation and systemic de-oxygenation, avoiding multi-organ failure. The main indications for ECMO support in pregnant women are cardiogenic shock, acute respiratory distress syndrome (ARDS), pulmonary embolism, and eclampsia. There are also fetal indications for ECMO, and they are fetal distress, hypoxic-ischemic encephalopathy (HIE), and twin-to-twin transfusion syndrome (TTTS). Until now, based on the outcomes of the numerous clinical studies conducted, ECMO has been shown to be a successful therapeutic strategy in cases where medical treatment has been unsuccessful. In well-selected pregnant patients, it appears to be safe and associated with a low risk of maternal and fetal complications. The aim of this review is to report the main properties of ECMO (VV and VA) and the indications for its use in pregnant women.

A Global Health Survey of People Who Vape but Never Smoked: Protocol for the VERITAS (Vaping Effects: Real-World International Surveillance) Study.

BACKGROUND: There is only limited information about the health effects of regular vaping. Research on the health status of people who used to smoke faces the challenge that previous smoking may have caused unknown health effects. Only studies of people who vape but have never smoked combustible cigarettes can enable the detection of harms attributable to vaping. Large prospective studies of well-characterized electronic cigarette users with and without a history of combustible cigarette smoking are warranted to establish the long-term effects of regular vaping on respiratory health. OBJECTIVE: We will conduct a global cross-sectional survey of individuals from 6 world regions. Respiratory symptoms will be assessed using a validated questionnaire-the Respiratory Symptom Experience Scale (RSES). Current vapers who are nonusers of other tobacco or nicotine products will be compared with matched controls who are nonusers of vapes and other tobacco or nicotine products. METHODS: This will be a multicountry, cross-sectional internet-based survey of 750 adults aged ≥18 years who satisfy the criteria for inclusion in either a cohort of people who exclusively vape and who are nonusers of other tobacco or nicotine products ("vapers cohort"; target N=500) or a cohort of nonvapers who are also nonusers of other tobacco or nicotine products ("controls cohort"; target N=250). The primary end point of the study is the RSES score. RSES scores of people in the "vapers cohort" will be compared with those of people in the "controls cohort." Additionally, the study will collect data to characterize patterns of vaping product use among the vapers cohort. Data collection will include information about the age initiation of using vape products, reasons for starting and continuing the use of vape products, specific types of products used, flavors and nicotine strengths of recently used products, as well as the frequency and intensity of product use in the past 30 days. RESULTS: Participant recruitment started in April 2023, and enrollment was completed by November 2023 with 748 participants. Results will be reported in 2024. CONCLUSIONS: This will be the first study providing key insights into respiratory health effects associated with using electronic cigarettes in people who vape with no established use of combustible cigarettes or other tobacco or nicotine products. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/54236.

Engineering sulfated polysaccharides and silk fibroin based injectable IPN hydrogels with stiffening and growth factor presentation abilities for cartilage tissue engineering.

The extracellular matrix (ECM) presents a framework for various biological cues and regulates homeostasis during both developing and mature stages of tissues. During development of cartilage, the ECM plays a critical role in endowing both biophysical and biochemical cues to the progenitor cells. Hence, designing microenvironments that recapitulate these biological cues as provided by the ECM during development may facilitate the engineering of cartilage tissue. In the present study, we fabricated an injectable interpenetrating hydrogel (IPN) system which serves as an artificial ECM and provides chondro-inductive niches for the differentiation of stem cells to chondrocytes. The hydrogel was designed to replicate the gradual stiffening (as a biophysical cue) and the presentation of growth factors (as a biochemical cue) as provided by the natural ECM of the tissue, thus exemplifying a biomimetic approach. This dynamic stiffening was achieved by incorporating silk fibroin, while the growth factor presentation was accomplished using sulfated-carboxymethyl cellulose. Silk fibroin and sulfated-carboxymethyl cellulose (s-CMC) were combined with tyraminated-carboxymethyl cellulose (t-CMC) and crosslinked using HRP/H2O2 to fabricate s-CMC/t-CMC/silk IPN hydrogels. Initially, the fabricated hydrogel imparted a soft microenvironment to promote chondrogenic differentiation, and with time it gradually stiffened to offer mechanical support to the joint. Additionally, the presence of s-CMC conferred the hydrogel with the property of sequestering cationic growth factors such as TGF-ß and allowing their prolonged presentation to the cells. More importantly, TGF-ß loaded in the developed hydrogel system remained active and induced chondrogenic differentiation of stem cells, resulting in the deposition of cartilage ECM components which was comparable to the hydrogels that were treated with TGF-ß provided through media. Overall, the developed hydrogel system acts as a reservoir of the necessary biological cues for cartilage regeneration and simultaneously provides mechanical support for load-bearing tissues such as cartilage.

Ventricular arrhythmia inducibility in porcine infarct model after stereotactic body radiation therapy.

BACKGROUND: Ventricular arrhythmia (VA) is the primary mechanism of sudden death in patients with structural heart disease. Cardiac stereotactic body radiation therapy (SBRT) delivered to the scar in the left ventricle significantly reduces the burden of VA. OBJECTIVE: The goal of this study was to investigate the impact of SBRT on scar morphology and VA inducibility in a porcine infarct model. METHODS: Myocardial infarction (MI) was created in 10 Yorkshire pigs involving the left anterior descending artery territory. Cardiac positron emission tomography and computed tomography were performed for targeted SBRT. Alternative pigs received SBRT at 25 Gy in a single fraction. The terminal experiment included endocardial mapping, programmed ventricular stimulation, and tissue harvesting. RESULTS: Of the 10 pigs infarcted, 2 died prematurely after MI and 8 (4 MI and 4 MI+SBRT) survived. Mean time from MI to SBRT was 48 ± 12 days, and mean time from SBRT to harvest was 32 ± 12 days. Scar was localized on intracardiac mapping in all pigs, and the scar was denser in the MI+SBRT compared with the MI-only group (33% ± 20% vs 14% ± 11%; P = .07). All 4 MI pigs had inducible VA during programmed stimulation, whereas only 1 of 4 pigs had inducible VA in the MI+SBRT arm (100% vs 25%; P = .07). No myocardial fibrosis was seen in the remote areas in either group. CONCLUSION: SBRT reduced VA inducibility in pigs with scarring after MI. Endocardial mapping revealed denser scar in pigs receiving SBRT compared with those that did not, suggesting that SBRT suppresses VA inducibility through better scar homogenization.

Bakuchiol nanoemulsion loaded electrospun nanofibers for the treatment of burn wounds.

The present work aims to develop and evaluate the wound healing potential of bakuchiol nanoemulsion loaded electrospun scaffolds. Since oxidative stress and microbial burden leads the burn wounds to become chronic and fatal to patients, a phytoconstituent, bakuchiol (BAK), was screened on the basis of antioxidant and antimicrobial potential which also defined its dose. Furthermore, BAK was incorporated into a nanoemulsion to enhance its therapeutic efficacy, reduce its dosage frequency, and maximize its stability. The present study is inclined towards the collaborative interaction of natural products and novel drug delivery systems to develop safe and therapeutically efficient systems for burn wound healing. The optimized nanoemulsion showed excellent antioxidant and antimicrobial potential against wound susceptible pathogens, i.e., Candida albicans and Methicillin-resistant Staphylococcus aureus which was further loaded into gelatin based hydrogel and nanofibrous scaffold system. The mesh structure of scaffolds was chosen as a suitable carrier system for wound healing process not only because it offers resemblance to skin's anatomy but is also capable of providing uniform distribution of wound biomarkers across the skin. The prepared nanofibers were assessed for their analgesic, anti-inflammatory, and wound healing potential which was observed to be significantly better than its gel formulation.

Directing ligament-mimetic bi-directional cell organization in scaffolds through zone-specific microarchitecture for ligament tissue engineering.

Ligament tissues exhibit zone-specific anisotropic cell organization. The cells in ligament-proper are longitudinally oriented, whereas, the cells in epiligament are circumferentially oriented. Therefore, scaffolds developed to regenerate ligament tissues should possess adequate architectural features to govern ligament-mimetic bi-directional cell organization. The scaffold architectural features along with ligament-mimetic cell organization may ultimately yield neo-tissues with ligament-like extracellular matrix (ECM) structure and biomechanical properties. Towards this goal, we fabricated a silk/gelatin-based core-shell scaffold (csSG) with zone-specific anisotropic architectural features, wherein, the core of the scaffold possessed longitudinally aligned pores while the shell of the scaffold possessed parallel microgrooves that are aligned circumferentially around the surface of the scaffold. The ligament-mimetic architectural features significantly improved the mechanical properties of the scaffold. Moreover, architectural features of the csSG scaffold governed zone-specific anisotropic organization of cells. The cells in the core were longitudinally oriented as observed in the ligament-proper and the cells on the shell were circumferentially oriented as observed in epiligament. This bi-directional cell orientation partially mimicked the complex cellular network in native ligament tissue. Additionally, both the core and the shell individually supported fibrogenic differentiation of stem cells which further improved their potential for ligament tissue engineering. Further, the aligned pores of the core could govern unidirectional organization of ECM deposited by cells which is crucial for regenerating anisotropic tissues like ligaments. Finally, when implanted subcutaneously in mice, the scaffolds retained their anisotropic architecture for at least 2 weeks, were biocompatible, supported cell infiltration and governed anisotropic organization of cells and ECM. Taken together, the fabricated biomimetic csSG scaffold, through its zone-specific architectural features, could govern ligament-mimetic cellular and ECM organization which is ultimately expected to achieve regeneration of ligament tissues with native-like hierarchical structure and biomechanical properties. Consequently, this study introduces bi-directional structural parameters as design criteria for developing scaffolds for ligament tissue engineering.

Bispectral Index Changes Following Boluses of Commonly Used Intravenous Medications During Volatile Anesthesia Identified From Retrospective Data.

BACKGROUND: Although patients are commonly monitored for depth of anesthesia, it is unclear to what extent administration of intravenous anesthetic medications may affect calculated bispectral (BIS) index values under general anesthesia. METHODS: In a retrospective analysis of electronic anesthesia records from an academic medical center, we examined BIS index changes associated with 14 different intravenous medications, as administered in routine practice, during volatile-based anesthesia using a novel screening approach. Discrete-time windows were identified in which only a single drug bolus was administered, and subsequent changes in the BIS index, concentration of volatile anesthetic, and arterial pressure were analyzed. Our primary outcome was change in BIS index, following drug administration. Adjusted 95% confidence intervals were compared to predetermined thresholds for clinical significance. Secondary sensitivity analyses examined the same outcomes, with available data separated according to differences in baseline volatile anesthetic concentrations, doses of the administered medications, and length of time window. RESULTS: The study cohort was comprised of data from 20,170 distinct cases, 54.7% of patients were men, with a median age of 55. In the primary analysis, ketamine at a median dose of 20 mg was associated with a median (confidence limits) increase in BIS index of 3.8 (2.5-5.0). Midazolam (median dose 2 mg) was associated with a median decrease in BIS index of 3.0 (1.5-4.5). Neither of these drug administrations occurred during time periods associated with changes in volatile anesthetic concentration. Analysis for dexmedetomidine was confounded by concomitant decreases in volatile anesthetic concentration. No other medication analyzed, including propofol and common opioids, was associated with a significant change in BIS index. Secondary analyses revealed that similar BIS index changes occurred when midazolam and ketamine were administered at different volatile anesthetic concentrations and different doses, and these changes persisted 11 to 20 minutes postadministration. CONCLUSIONS: Modest, but persistent changes in BIS index occurred following doses of ketamine (increase) and midazolam (decrease) during periods of stable volatile anesthetic administration.

REMAP Periop: a randomised, embedded, multifactorial adaptive platform trial protocol for perioperative medicine to determine the optimal enhanced recovery pathway components in complex abdominal surgery patients within a US healthcare system.

INTRODUCTION: Implementation of enhanced recovery pathways (ERPs) has resulted in improved patient-centred outcomes and decreased costs. However, there is a lack of high-level evidence for many ERP elements. We have designed a randomised, embedded, multifactorial, adaptive platform perioperative medicine (REMAP Periop) trial to evaluate the effectiveness of several perioperative therapies for patients undergoing complex abdominal surgery as part of an ERP. This trial will begin with two domains: postoperative nausea/vomiting (PONV) prophylaxis and regional/neuraxial analgesia. Patients enrolled in the trial will be randomised to arms within both domains, with the possibility of adding additional domains in the future. METHODS AND ANALYSIS: In the PONV domain, patients are randomised to optimal versus supraoptimal prophylactic regimens. In the regional/neuraxial domain, patients are randomised to one of five different single-injection techniques/combination of techniques. The primary study endpoint is hospital-free days at 30 days, with additional domain-specific secondary endpoints of PONV incidence and postoperative opioid consumption. The efficacy of an intervention arm within a given domain will be evaluated at regular interim analyses using Bayesian statistical analysis. At the beginning of the trial, participants will have an equal probability of being allocated to any given intervention within a domain (ie, simple 1:1 randomisation), with response adaptive randomisation guiding changes to allocation ratios after interim analyses when applicable based on prespecified statistical triggers. Triggers met at interim analysis may also result in intervention dropping. ETHICS AND DISSEMINATION: The core protocol and domain-specific appendices were approved by the University of Pittsburgh Institutional Review Board. A waiver of informed consent was obtained for this trial. Trial results will be announced to the public and healthcare providers once prespecified statistical triggers of interest are reached as described in the core protocol, and the most favourable interventions will then be implemented as a standardised institutional protocol. TRIAL REGISTRATION NUMBER: NCT04606264.

Perylene diimide-based radical anions for the rapid detection of picomolar H2O2 in an aqueous medium.

The formation of radical anions (PDI 1˙-) using H2S as a sacrificial electron donor in 50% HEPES buffer-THF solution is reported. PDI 1˙- was confirmed by optical, I-V plot, CV, DPV, NOBF4 and EPR studies. PDI 1˙- has a half-life of 96 minutes in solution and 11 days in the solid state without any additive. The formation of PDI 1˙- was confirmed by AFM and SEM. PDI 1˙- can be used for the detection of 26.6 pM of H2O2 supported by optical and CV data.

Flexible, humidity- and contamination-resistant superhydrophobic MXene-based electrospun triboelectric nanogenerators for distributed energy harvesting applications.

The low surface-charge density, poor stability and irreparable surface of triboelectric materials under harsh environments are still some obstacles for developing high-performance triboelectric nanogenerators (TENGs). In particular, a two-dimensional MXene material's surface is likely to be corroded by water molecules under high humidity conditions owing to its hydrophilic nature, limiting the output performance and stability of TENGs. Herein, an approach for fabricating a humidity- and contamination-resistant MXene-based TENG is established using the electrospinning technique. First, nanofibrous layers of MXene/MoS2 composites blended in a cellulosic polymer matrix were prepared, benefitting the high surface roughness and controlled air-trapping pores. Furthermore, the prepared nanofibrous layers were chemically modified with stearic acid (SA), which enhances the hydrophobicity and electronegativity of MXene/MoS2 composites. In a typical synthesis, four different compositions of MXene/MoS2/cellulose acetate nanofibers were prepared, which illustrates that an increasing concentration of MoS2 could effectively tune the surface oxidation, hydrophilic nature, and surface roughness of MXene as well as induce a piezoelectricity-enhanced triboelectric potential. On the other side, the SA modification ultimately generated a superhydrophobic surface with low surface energy and a high water contact angle of ∼154°. The integrated TENG displayed an enhanced output voltage of ∼140 V and an instantaneous power density of ∼2975 mW cm-2 with long-term stability under high humidity conditions. Additionally, the self-cleaning properties were demonstrated, ensuring the sustainability and reusability of the TENG in a contaminated environment. Moreover, the fabricated MXene-based superhydrophobic layer can harvest the energy on dripping water droplets based on the liquid-solid contact-electrification TENG mode. Overall, this work paves the way for the design and development of humidity- and contamination-resistant triboelectric materials and guides the study of harvesting of distributed environmental energy efficiently.

Thoracic Dorsal Root Ganglion Application of Resiniferatoxin Reduces Myocardial Ischemia-Induced Ventricular Arrhythmias.

BACKGROUND: A myocardial ischemia/reperfusion (IR) injury activates the transient receptor potential vanilloid 1 (TRPV1) dorsal root ganglion (DRG) neurons. The activation of TRPV1 DRG neurons triggers the spinal dorsal horn and the sympathetic preganglionic neurons in the spinal intermediolateral column, which results in sympathoexcitation. In this study, we hypothesize that the selective epidural administration of resiniferatoxin (RTX) to DRGs may provide cardioprotection against ventricular arrhythmias by inhibiting afferent neurotransmission during IR injury. METHODS: Yorkshire pigs (n = 21) were assigned to either the sham, IR, or IR + RTX group. A laminectomy and sternotomy were performed on the anesthetized animals to expose the left T2-T4 spinal dorsal root and the heart for IR intervention, respectively. RTX (50 µg) was administered to the DRGs in the IR + RTX group. The activation recovery interval (ARI) was measured as a surrogate for the action potential duration (APD). Arrhythmia risk was investigated by assessing the dispersion of repolarization (DOR), a marker of arrhythmogenicity, and measuring the arrhythmia score and the number of non-sustained ventricular tachycardias (VTs). TRPV1 and calcitonin gene-related peptide (CGRP) expressions in DRGs and CGRP expression in the spinal cord were assessed using immunohistochemistry. RESULTS: The RTX mitigated IR-induced ARI shortening (-105 ms ± 13 ms in IR vs. -65 ms ± 11 ms in IR + RTX, p = 0.028) and DOR augmentation (7093 ms2 ± 701 ms2 in IR vs. 3788 ms2 ± 1161 ms2 in IR + RTX, p = 0.020). The arrhythmia score and VT episodes during an IR were decreased by RTX (arrhythmia score: 8.01 ± 1.44 in IR vs. 3.70 ± 0.81 in IR + RTX, p = 0.037. number of VT episodes: 12.00 ± 3.29 in IR vs. 0.57 ± 0.3 in IR + RTX, p = 0.002). The CGRP expression in the DRGs and spinal cord was decreased by RTX (DRGs: 6.8% ± 1.3% in IR vs. 0.6% ± 0.2% in IR + RTX, p < 0.001. Spinal cord: 12.0% ± 2.6% in IR vs. 4.5% ± 0.8% in IR + RTX, p = 0.047). CONCLUSIONS: The administration of RTX locally to thoracic DRGs reduces ventricular arrhythmia in a porcine model of IR, likely by inhibiting spinal afferent hyperactivity in the cardio-spinal sympathetic pathways.

Real-time in vivo thoracic spinal glutamate sensing during myocardial ischemia.

In the spinal cord, glutamate serves as the primary excitatory neurotransmitter. Monitoring spinal glutamate concentrations offers valuable insights into spinal neural processing. Consequently, spinal glutamate concentration has the potential to emerge as a useful biomarker for conditions characterized by increased spinal neural network activity, especially when uptake systems become dysfunctional. In this study, we developed a multichannel custom-made flexible glutamate-sensing probe for the large-animal model that is capable of measuring extracellular glutamate concentrations in real time and in vivo. We assessed the probe's sensitivity and specificity through in vitro and ex vivo experiments. Remarkably, this developed probe demonstrates nearly instantaneous glutamate detection and allows continuous monitoring of glutamate concentrations. Furthermore, we evaluated the mechanical and sensing performance of the probe in vivo, within the pig spinal cord. Moreover, we applied the glutamate-sensing method using the flexible probe in the context of myocardial ischemia-reperfusion (I/R) injury. During I/R injury, cardiac sensory neurons in the dorsal root ganglion transmit excitatory signals to the spinal cord, resulting in sympathetic activation that potentially leads to fatal arrhythmias. We have successfully shown that our developed glutamate-sensing method can detect this spinal network excitation during myocardial ischemia. This study illustrates a novel technique for measuring spinal glutamate at different spinal cord levels as a surrogate for the spinal neural network activity during cardiac interventions that engage the cardio-spinal neural pathway.NEW & NOTEWORTHY In this study, we have developed a new flexible sensing probe to perform an in vivo measurement of spinal glutamate signaling in a large animal model. Our initial investigations involved precise testing of this probe in both in vitro and ex vivo environments. We accurately assessed the sensitivity and specificity of our glutamate-sensing probe and demonstrated its performance. We also evaluated the performance of our developed flexible probe during the insertion and compared it with the stiff probe during animal movement. Subsequently, we used this innovative technique to monitor the spinal glutamate signaling during myocardial ischemia and reperfusion that can cause fatal ventricular arrhythmias. We showed that glutamate concentration increases during the myocardial ischemia, persists during the reperfusion, and is associated with sympathoexcitation and increases in myocardial substrate excitability.

Converse modulation of Wnt/ß-catenin signaling during expansion and differentiation phases of Infrapatellar fat pad-derived MSCs for improved engineering of hyaline cartilage.

Mesenchymal stem cells (MSCs) are potential candidates in cell-based therapy for cartilage repair and regeneration. However, during chondrogenic differentiation, MSCs undergo undesirable hypertrophic maturation. This poses a risk of ossification in the neo-tissue formed that eventually impedes the clinical use of MSCs for cartilage repair. TGF-ß is a potent growth factor used for chondrogenic differentiation of MSCs, however, its role in hypertrophy remains ambiguous. In the present work, we decipher that TGF-ß activates Wnt/ß-catenin signaling through SMAD3 and increases the propensity of Infrapatellar fat pad derived MSCs (IFP-MSCs) towards hypertrophy. Notably, inhibiting TGF-ß induced Wnt/ß-catenin signaling suppresses hypertrophic progression and enhances chondrogenic ability of IFP-MSCs in plasma hydrogels. Additionally, we demonstrate that activating Wnt signaling during expansion phase, promotes proliferation and reduces senescence, while improving stemness of IFP-MSCs. Thus, conversely modulating Wnt signaling in vitro during expansion and differentiation phases generates hyaline-like cartilage with minimal hypertrophy. Importantly, pre-treatment of IFP-MSCs encapsulated in plasma hydrogel with Wnt modulators followed by subcutaneous implantation in nude mice resulted in formation of a cartilage tissue with negligible calcification. Overall, this study provides technological advancement on targeting Wnt/ß-catenin pathway in a 3D scaffold, while maintaining the standard chondro-induction protocol to overcome the challenges associated with the clinical use of MSCs to engineer hyaline cartilage.

Development and Validation of a Machine Learning Model to Identify Patients Before Surgery at High Risk for Postoperative Adverse Events.

Importance: Identifying patients at high risk of adverse outcomes prior to surgery may allow for interventions associated with improved postoperative outcomes; however, few tools exist for automated prediction. Objective: To evaluate the accuracy of an automated machine-learning model in the identification of patients at high risk of adverse outcomes from surgery using only data in the electronic health record. Design, Setting, and Participants: This prognostic study was conducted among 1 477 561 patients undergoing surgery at 20 community and tertiary care hospitals in the University of Pittsburgh Medical Center (UPMC) health network. The study included 3 phases: (1) building and validating a model on a retrospective population, (2) testing model accuracy on a retrospective population, and (3) validating the model prospectively in clinical care. A gradient-boosted decision tree machine learning method was used for developing a preoperative surgical risk prediction tool. The Shapley additive explanations method was used for model interpretability and further validation. Accuracy was compared between the UPMC model and National Surgical Quality Improvement Program (NSQIP) surgical risk calculator for predicting mortality. Data were analyzed from September through December 2021. Exposure: Undergoing any type of surgical procedure. Main Outcomes and Measures: Postoperative mortality and major adverse cardiac and cerebrovascular events (MACCEs) at 30 days were evaluated. Results: Among 1 477 561 patients included in model development (806 148 females [54.5%; mean [SD] age, 56.8 [17.9] years), 1 016 966 patient encounters were used for training and 254 242 separate encounters were used for testing the model. After deployment in clinical use, another 206 353 patients were prospectively evaluated; an additional 902 patients were selected for comparing the accuracy of the UPMC model and NSQIP tool for predicting mortality. The area under the receiver operating characteristic curve (AUROC) for mortality was 0.972 (95% CI, 0.971-0.973) for the training set and 0.946 (95% CI, 0.943-0.948) for the test set. The AUROC for MACCE and mortality was 0.923 (95% CI, 0.922-0.924) on the training and 0.899 (95% CI, 0.896-0.902) on the test set. In prospective evaluation, the AUROC for mortality was 0.956 (95% CI, 0.953-0.959), sensitivity was 2148 of 2517 patients (85.3%), specificity was 186 286 of 203 836 patients (91.4%), and negative predictive value was 186 286 of 186 655 patients (99.8%). The model outperformed the NSQIP tool as measured by AUROC (0.945 [95% CI, 0.914-0.977] vs 0.897 [95% CI, 0.854-0.941], for a difference of 0.048), specificity (0.87 [95% CI, 0.83-0.89] vs 0.68 [95% CI, 0.65-0.69]), and accuracy (0.85 [95% CI, 0.82-0.87] vs 0.69 [95% CI, 0.66, 0.72]). Conclusions and Relevance: This study found that an automated machine learning model was accurate in identifying patients undergoing surgery who were at high risk of adverse outcomes using only preoperative variables within the electronic health record, with superior performance compared with the NSQIP calculator. These findings suggest that using this model to identify patients at increased risk of adverse outcomes prior to surgery may allow for individualized perioperative care, which may be associated with improved outcomes.