Genome-wide DNA methylation and transcriptomic analysis of liver tissues subjected to early ischemia/reperfusion injury upon human liver transplantation.

INTRODUCTION AND OBJECTIVES: Epigenetic changes represent a mechanism connecting external stresses with long-term modifications of gene expression programs. In solid organ transplantation, ischemia-reperfusion injury (IRI) appears to induce epigenomic changes in the graft, although the currently available data are extremely limited. The present study aimed to characterize variations in DNA methylation and their effects on the transcriptome in liver transplantation from brain-dead donors. PATIENTS AND METHODS: 12 liver grafts were evaluated through serial biopsies at different timings in the procurement-transplantation process: T0 (warm procurement, in donor), T1 (bench surgery), and T2 (after reperfusion, in recipient). DNA methylation (DNAm) and transcriptome profiles of biopsies were analyzed using microarrays and RNAseq. RESULTS: Significant variations in DNAm were identified, particularly between T2 and T0. Functional enrichment of the best 1000 ranked differentially methylated promoters demonstrated that 387 hypermethylated and 613 hypomethylated promoters were involved in spliceosomal assembly and response to biotic stimuli, and inflammatory immune responses, respectively. At the transcriptome level, T2 vs. T0 showed an upregulation of 337 and downregulation of 61 genes, collectively involved in TNF-α, NFKB, and interleukin signaling. Cell enrichment analysis individuates macrophages, monocytes, and neutrophils as the most significant tissue-cell type in the response. CONCLUSIONS: In the process of liver graft procurement-transplantation, IRI induces significant epigenetic changes that primarily act on the signaling pathways of inflammatory responses dependent on TNF-α, NFKB, and interleukins. Our DNAm datasets are the early IRI methylome literature and will serve as a launch point for studying the impact of epigenetic modification in IRI.

There is high variability in quantitative measurement techniques in glenohumeral capsular measurements for shoulder instability: A systematic review.

PURPOSE: Instability of the glenohumeral joint remains a complex clinical issue with high rates of surgical failure and significant morbidity. Advances in specific radiologic measurements involving the glenoid and the humerus have provided insight into glenohumeral pathology, which can be corrected surgically towards improving patient outcomes. The contributions of capsular pathology to ongoing instability remain unclear. The purpose of this study is to provide a systematic review of existing glenohumeral capsular measurement techniques published in the last 15 years. METHODS: A systematic review of multiple databases was performed following PRISMA guidelines for all primary research articles between 2008 and 2023 with quantitative measurements of the glenohumeral capsule in patients with instability, including anterior, posterior and multi-directional instability. RESULTS: There were a total of 14 articles meeting the inclusion criteria. High variability in measurement methodology across studies was observed, including variable amounts of intra-articular contrast, heterogeneity among magnetic resonance sequence acquisitions, differences in measurements performed and the specific approach taken to compute each measurement. CONCLUSION: There is a need for standardization of methods in the measurement of glenohumeral capsular pathology in the setting of glenohumeral instability to allow for cross-study analysis. LEVEL OF EVIDENCE: Level III.

The Gut Microbiome and Joint Microbiome Show Alterations in Patients with Knee Osteoarthritis Versus Controls: A Systematic Review.

PURPOSE: To assess the current scientific literature on the microbiome's relationship with knee osteoarthritis (OA), with specific focuses on the gut microbiome-joint axis and joint microbiome-joint axis. METHODS: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, searching PubMed, Embase, and Cochrane databases for relevant English-language clinical studies on the gut and/or joint microbiomes' association with knee OA in humans. Bias was evaluated using the methodological index for non-randomized studies score. RESULTS: Thirty-five thousand bacterial species comprise the gut microbiome; approximately 90% are members of the phyla Bacteroides and Firmicutes. Symbiosis between the gut microbiome and host under normal physiological conditions positively affects host growth, development, immunity, and longevity. Gut microbiome imbalance can negatively influence various physiological processes, including immune response, inflammation, metabolism, and joint health including development of knee OA. In addition, next generation gene sequencing suggests the presence of microorganisms in the synovial fluid of osteoarthritic knees, and distinct microbiome profiles detected are presumed to play a role in the development of OA. With regard to the gut microbiome, consistent alterations in microbial composition between OA patients and controls are noted, in addition to several associations between certain gut bacteria with OA-related knee pain, patient-reported outcome measure performance, imaging findings, and changes in metabolic and inflammatory pathways. Regarding the joint microbiome, studies revealed increased levels of lipopolysaccharide (LPS) and LPS-binding protein in synovial fluid are associated with activated macrophages, and correlated with worsened osteophyte severity, joint space narrowing, and pain scores in knee OA patients. In addition, studies demonstrated various microbial composition differences in OA patients compared to control, with certain joint microbes directly associated with OA pathogenesis, inflammation, and metabolic dysregulation. CONCLUSIONS: The gut microbiome-joint axis and joint microbiome shows alterations in microbial composition between osteoarthritic patients and controls. These alterations are associated with perturbations of metabolic and inflammatory pathways, imaging findings, osteoarthritis-related pain, and patient reported outcome measure performance. LEVEL OF EVIDENCE: Systematic Review; Level III.

Obstructive sleep apnea severity, circulating biomarkers, and cancer risk.

STUDY OBJECTIVES: To determine if obstructive sleep apnea (OSA) severity and/or biomarkers of inflammation/angiogenesis are associated with incident cancer in this clinical cohort. METHODS: Consenting adult patients at the University of British Columbia Hospital between 2003-2014 completed a questionnaire about their medical history and sleep habits prior to undergoing a polysomnogram (PSG). Blood samples were collected the morning after PSG and processed for biomarkers of inflammation and angiogenesis. The clinical, PSG, and biomarker data were linked to the British Columbia Cancer Registry to ascertain incident cancer diagnoses. Cox proportional hazard regression were used to assess the association between OSA severity and biomarker concentrations with cancer risk. RESULTS: A total of 1,990 patients were included in the analysis with a mean follow-up time of 12.8 years; 181 of them (9.1%) developed cancer after PSG. OSA severity was significantly associated with cancer risk after controlling for relevant covariates (hazard ratio (HR) = 1.08 per 10 events/h apnea-hypopnea index (AHI) increase, CI = 1.02-1.15, p=0.015). In an exploratory analysis, two biomarkers were significantly associated with an increased cancer risk after controlling for relevant covariates (HR per interquartile range (IQR) pg/mL increase of endostatin = 1.45, CI = 1.12-1.87, p=0.01 and HR for IQR pg/mL increase of VCAM-1 = 1.48, CI = 1.04-2.11, p=0.03, respectively). CONCLUSIONS: OSA severity was an independent risk factor for cancer. Furthermore, two circulating markers were significantly associated with cancer risk. If these preliminary findings can be reproduced in other cohorts, biomarkers could potentially be used to prognosticate OSA patients with respect to cancer risk.

Arthroscopic Debridement of Mild and Moderate Knee Osteoarthritis Results in Clinical Improvement at Short-Term Follow-Up: A Systematic Review.

PURPOSE: To report the clinical outcomes of arthroscopic debridement for the treatment of Kellgren-Lawrence (KL) grade I and II (mild) and III (moderate) knee osteoarthritis (OA) at a minimum 1-year follow-up. METHODS: A systematic review of primary literature was performed in concordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using the Medline, Embase, and Cochrane databases for studies regarding arthroscopic debridement/chondroplasty for management of knee OA at a minimum 1-year follow-up. Studies were included if they included KL grades I to III or dichotomized clinical outcomes by KL grade. The primary outcome was patient-reported outcome measures (PROMs) at the final follow-up. Bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS) score. RESULTS: Eight studies including a total of 773 patients met inclusion criteria (range of patients in each study, 31-214). Mean age of patients ranged from 35.5 to 64 years, with most studies having a mean patient age of 55 to 65 years. Mean follow-up ranged from 1.5 to 10 years. Seven of the 8 (87.5%) studies reported good to excellent PROMs at a minimum 1- to 4-year follow-up after arthroscopic debridement. Improvements in PROMs were superior in patients with less severe knee OA (KL I-II) in comparison to KL III in most studies. Conversion to arthroplasty ranged from 7.6% to 50% in KL III patients compared with 0% to 4.5% in KL I-II patients after arthroscopic debridement. Two of the 3 studies with at least a 4-year clinical follow-up reported that clinical improvements diminished with time (improvements no longer significant in total Western Ontario and McMaster Universities Osteoarthritis Index score). The lone randomized controlled trial was the only investigation that did not find a benefit of arthroscopic debridement over quality nonoperative care. MINORS scores ranged from 6 to 10 (mean, 8.0) for the 5 nonrandomized studies without controls. CONCLUSIONS: Arthroscopic debridement for the management of mild to moderate knee OA is effective at short-term follow-up in patients who have exhausted conservative care. There is limited evidence demonstrating the durability of improvement following arthroscopic debridement after 2 years. LEVEL OF EVIDENCE: Level IV, systematic review of Level I to IV studies.

Orthopaedic Musculoskeletal Biologics Research Impacts Patient Care: The Second Annual Arthroscopy Orthobiologics Virtual Special Issue.

The field of orthobiologics is rapidly evolving, offering clinicians a shift in treatment from symptom relief to the potential for disease modification and tissue repair. These agents, derived from autologous tissues, components of blood, and growth factors, are used as surgical adjuncts or as standalone treatments. Their clinical applications are expanding to encompass a variety of conditions, supported by a growing base of research efforts. Arthroscopy and its companion publications are committed to evidence-based research with a robust history of publications that enhance clinical decision-making and impact patient care. This curated collection of articles highlights the year's most compelling advancements in orthopaedic musculoskeletal biologics research.

Bioabsorbable Screw Fixation Provides Good Results With Low Failure Rates at Mid-term Follow-up of Stable Osteochondritis Dissecans Lesions That Do Not Improve With Initial Conservative Treatment.

Purpose: To evaluate the clinical and radiographic outcomes of patients who have undergone bioabsorbable screw fixation for intact, stable grade I and II osteochondritis dissecans (OCD) lesions for which at least 6 months of conservative management has failed. Methods: A retrospective review of prospectively collected data from a single institution was performed to identify patients who underwent internal fixation of stable grade I and II OCD lesions (according to the Guhl classification) between January 2010 and January 2020. Patients were included regardless of the presence of concomitant procedures. The inclusion criteria consisted of (1) primary surgery, (2) failure of at least 6 months of conservative management, (3) the use of a bioabsorbable screw (or screws), and (4) minimum 2-year clinical follow-up. Radiographs were obtained at a minimum of 1 year postoperatively. Patient demographic characteristics, clinical patient-reported outcomes, complications, and failure rates were noted. Results: Twenty-four knees among 23 patients (96% follow-up) were analyzed and followed up for 6.36 ± 3.42 years (range, 2.0-12.7 years). Patients showed statistically significant postoperative improvements in all patient-reported outcomes including the Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score subscales (P < .05). In 3 knees (12%), a reoperation was required due to failure at an average of 3.64 years after the index procedure. No specific complications were attributed to the use of bioabsorbable screws. Patients in whom primary surgical treatment failed did not differ in demographic characteristics, arthroscopic findings, or surgical treatment from those who had successful treatment. Conclusions: Internal fixation of stable grade I and II OCD lesions with bioabsorbable screws produces reliable results with a 12% rate of failure in appropriately indicated patients in whom at least 6 months of conservative management has failed. Clinical outcomes improved significantly during the mid-term follow-up period. Level of Evidence: Level IV, therapeutic case series.

Peptide-Drug Conjugates: An Emerging Direction for the Next Generation of Peptide Therapeutics.

Building on recent advances in peptide science, medicinal chemists have developed a hybrid class of bioconjugates, called peptide-drug conjugates, that demonstrate improved efficacy compared to peptides and small molecules independently. In this Perspective, we discuss how the conjugation of synergistic peptides and small molecules can be used to overcome complex disease states and resistance mechanisms that have eluded contemporary therapies because of their multi-component activity. We highlight how peptide-drug conjugates display a multi-factor therapeutic mechanism similar to that of antibody-drug conjugates but also demonstrate improved therapeutic properties such as less-severe off-target effects and conjugation strategies with greater site-specificity. The many considerations that go into peptide-drug conjugate design and optimization, such as peptide/small-molecule pairing and chemo-selective chemistries, are discussed. We also examine several peptide-drug conjugate series that demonstrate notable activity toward complex disease states such as neurodegenerative disorders and inflammation, as well as viral and bacterial targets with established resistance mechanisms.

Suture Augmentation of a Four-Strand Semitendinosus Graft Improves Time-Zero Biomechanical Properties.

PURPOSE: To compare the time-zero biomechanical properties of hamstring graft preparations with or without suture augmentation for anterior cruciate ligament reconstruction (ACLR) in a full-construct cadaveric model. METHODS: Hamstring grafts were harvested from 24 fresh frozen human cadavers and prepared in 1 of 3 ways: quadrupled SemiTendinosus (SemiT), and quadrupled SemiT with suture augmentation (SemiT+2.0-mm tape or SemiT+1.3-mm tape; n = 8 per group). Adjustable loop suspensory implants and cortical buttons were used for fixation on a porcine tibia and acrylic block. Testing included force-controlled cyclic loading at 250 N and 400 N followed by load to failure. RESULTS: The 2 suture augmentation groups had less total elongation and increased stiffness compared to the nonsuture-augmented group (P = .025). The SemiT+2.0-mm tape group had 36% less total elongation and 34% increased stiffness compared to SemiT+1.3mm tape (P < .001). CONCLUSIONS: Suture augmentation improves construct biomechanics at time zero following hamstring tendon ACLR. Augmentation with 2.0-mm tape suture improves construct biomechanics compared to 1.3-mm tape suture. CLINICAL RELEVANCE: Independent suture augmentation of a quadrupled SemiT graft improves ACLR construct biomechanics. Outcomes were improved with augmentation using 2.0-mm tape suture compared to 1.3-mm tape suture.

Time-Driven Activity-Based Costing Analysis Identifies Use of Consumables and Operating Room Time as Factors Associated With Increased Cost of Outpatient Primary Hip Arthroscopic Labral Repair.

PURPOSE: To use time-driven, activity-based costing (TDABC) methodology to 1) investigate drivers of cost variation and 2) elucidate preoperative and intraoperative factors associated with increased cost of outpatient arthroscopic hip labral repair. METHODS: A retrospective analysis of data from January 2020 to October 2021 was performed. Patients undergoing primary hip arthroscopy for labral repair in the outpatient setting were included. Indexed TDABC data from avant-garde health's analytics platform were used to represent cost-of-care breakdowns. Patients in the top decile of cost were defined as high cost, and cost category variance was determined as a percent increase between high and low cost. Analyses tested for associations between preoperative and perioperative factors with total cost. Surgical procedures performed concomitantly to labral repair were included in subanalyses. RESULTS: Data from 151 patients were analyzed. Consumables made up 61% of total outpatient cost with surgical personnel costs (30%) being the second largest category. The average total cost was 19% higher for patients in the top decile of cost compared to the remainder of the cohort. Factors contributing to this difference were implants (36% higher), surgical personnel (20% higher), and operating room (OR) consumables (15% higher). Multivariate linear regression modeling indicated that OR time (Standardized ß = 0.504; P < .001) and anchor quantity (standardized ß = 0.443; P < .001) were significant predictors of increased cost. Femoroplasty (Unstandardized ß = 15.274; P = .010), chondroplasty (Unstandardized ß = 8.860; P = .009), excision of os acetabuli (unstandardized ß = 13.619; P = .041), and trochanteric bursectomy (Unstandardized ß = 21.176; P = .009) were also all independently associated with increasing operating time. CONCLUSION: TDABC analysis showed that OR consumables and implants were the largest drivers of cost for the procedure. OR time was also shown to be a significant predictor of increased costs. LEVEL OF EVIDENCE: Level IV, economic analysis.

An assessment of factors associated with early postoperative stiffness in arthroscopic rotator cuff repair.

BACKGROUND: Postoperative stiffness affects up to 20% of patients following arthroscopic rotator cuff repair. Recent evidence indicates that early postoperative stiffness may associated with lower retear rates. This study aimed to identify the independent predictors of early postoperative stiffness. METHODS: A retrospective cohort study of 1526 rotator cuff repairs was performed. Range of motion at 6-week postop was used to identify stiff patients. Stiffness was defined as external rotation <27.5o or forward flexion <145o . Multiple logistic regression analysis was used to identify the independent predictors of 6-week stiffness. RESULTS: The independent predictors for external rotation stiffness at 6-week postop were more recent cases (Wald = 60), restricted preoperative external rotation (Wald = 36), younger age (Wald = 21) and poorer surgeon-ranked tissue quality (Wald = 15). The independent predictors for forward flexion stiffness were more recent cases (Wald = 101), restricted preoperative forward flexion (Wald = 16) and external rotation (Wald = 13) and female patients (Wald = 12). All patients that developed early postoperative stiffness had recovered range of motion by 6 months to preoperative levels (P < 0.0001). A significantly greater proportion of younger patients (40-49) developed postoperative stiffness when compared to older patients aged 50-59 (P < 0.0062), 70-79 (P < 0.0126) and 80-89 (P < 0.004). Patients that retore had significantly greater average 6-week postoperative range of motion. CONCLUSIONS: Patients earlier in the study were found to have greater postoperative range of motion, which coincided with a more aggressive rehabilitation program with less immobilization. Thus, the data supports the hypothesis that a temporary period of shoulder stiffness facilitates tendon repair and ultimately a better outcome post rotator cuff repair.

Predominance of Canine Parainfluenza Virus and Mycoplasma in Canine Infectious Respiratory Disease Complex in Dogs.

Canine infectious respiratory disease complex (CIRDC) is caused by different viruses and bacteria. Viruses associated with CIRDC include canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine influenza virus (CIV), canine herpesvirus type 1 (CHV-1), canine respiratory coronavirus (CRCoV), and canine parainfluenza virus (CPIV). Bacteria associated with CIRDC include Bordetella bronchiseptica, Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), and Mycoplasma spp. The present study examined the prevalence of CIRDC pathogens in specimens received by a Veterinary Diagnostic Laboratory in Georgia, USA., from 2018 to 2022. Out of 459 cases, viral agents were detected in 34% of cases and bacterial agents were detected in 58% of cases. A single pathogen was detected in 31% of cases, while two or more pathogens were identified in 24% of cases. The percentages of viral agents identified were CAV-2 (4%), CDV (3%), CPIV (16%), CRCoV (7%), and CIV (2%). The percentages of bacterial agents were B. bronchiseptica (10%), Mycoplasma canis (24%), Mycoplasma cynos (21%), and S. zooepidemicus (2%). Over the five-year period, the positive cases ranged from 2-4% for CAV-2, 1-7% for CDV, 1-4% for CHV-1, 9-22% for CPIV, 4-13% for CRCoV, and 1-4% for CIV. Overall, the most prevalent pathogens associated with CIRDC were CPIV, M. canis, and M. cynos.

Medical Students' Perceptions of Orthopedics as a Career for Women.

OBJECTIVES: To determine potential factors influencing female medical students' interest and subsequent application to orthopedics, and to evaluate female and male medical students' perceptions of women in the field of orthopedics. METHODS: An institutional review board-approved survey was distributed in March 2020 and subsequently in April 2022 to medical students in the classes of 2023 and 2024 at the University of Alabama at Birmingham Heersink School of Medicine. Study data were collected and managed using REDCap electronic data capture. An e-mail link to the REDCap survey was sent to students across the southeast region of the United States, followed by three reminder e-mails. All 25 allopathic medical schools in the southeastern United States with an Orthopedics Interest Group listed on their institution's Web site were invited to participate in the study. Nine Orthopedics Interest Group leaders interested in participating were asked to provide the researchers with a list of fourth-year medical students who attended an event hosted by that group (215). A total of 39 respondents who completed the survey were included in this study. RESULTS: Overall, the majority of students (n = 35, 90%) believed that women faced more barriers to a career in orthopedics than did men. The most significant barriers to women entering the field of orthopedics were the perceived expectations of an orthopedic surgeon (n = 34, 87%), difficulty balancing career and family (n = 28, 72%), and demanding schedule (n = 13, 33%). CONCLUSIONS: This study demonstrates that both male and female medical students believe there are significant additional barriers to success for women in the field. Study participants report that expectations set by physicians, other healthcare professionals, and patients contribute to creating greater barriers that deter medical students interested in orthopedics from ultimately applying to the specialty.

Biomechanical Comparison of Synthetic Polytetrafluoroethylene (PTFE) vs Human Dermal Allograft (HDA), 2 vs 3 Glenoid Anchors, and Suture vs Minitape in Superior Capsule Reconstruction.

Background: Superior capsule reconstruction (SCR) is an option for the treatment of massive, irreparable rotator cuff tears. However, which materials yield the strongest constructs remains undetermined. Purposes: We sought to investigate whether SCR with polytetrafluoroethylene (PTFE) or human dermal allograft (HDA), 2 or 3 glenoid anchors, and suture or minitape resulted in better failure load properties at the patch-glenoid interface. Methods: We conducted a biomechanical study in 30 glenoid-sided SCR repairs in Sawbones models divided into 5 groups. Each was pulled to failure to assess mode of failure, peak load (N), stiffness (N/mm), yield load (N), peak energy (N m), and ultimate energy (N m). The 5 groups were as follows: group 1-PTFE, 2 anchors, and suture; group 2-PTFE, 2 anchors, and minitape; group 3-HDA, 2 anchors, and suture; group 4-HDA, 2 anchors, and minitape; group 5-PTFE, 3 anchors, and minitape. Results: Repairs failed by button-holing of suture/minitape. Group 5 had greater peak load, stiffness, yield load, and peak energy (384 ± 62 N; 24 ± 3 N/mm; 343 ± 42 N; 4 ± 2 N m) than group 3 (226 ± 67 N; 16 ± 4 N/mm; 194 ± 74 N; 2 ± 1 N m) or group 4 (274 ± 62 N; 17 ± 4 N/mm; 244 ± 50 N; 2 ± 1 N m) and greater ultimate energy (8 ± 3 N m) than all other groups. Conclusions: This biomechanical study of SCR repairs in Sawbones models found that yield load was greater in PTFE than HDA, 3 anchors were better than 2, and minitape was no better than suture.

The rs579459 ABO gene polymorphism and risk of incident cardiovascular events in obstructive sleep apnea: a pilot study.

PURPOSE: We have previously shown that the TT genotype (rs579459 location of the ABO gene) is significantly associated with circulating levels of e-selectin in patients with suspected obstructive sleep apnea (OSA). We hypothesized that this genotype would be associated with incident cardiovascular disease (CVD). METHODS: Patients with suspected OSA who had a full diagnostic polysomnogram from 2003 to 2011 were recruited; CV events occurring within 8 years of polysomnography were identified by linkage to provincial health databases. Cox proportional hazards models were used to evaluate the incidence of first CV events as a function of the rs579459 genotype. RESULTS: In this targeted study, 408 patients were studied, and 39 incident events were identified. A larger proportion of patients with the TT genotype had an event (31/247; 12.6%) than the CT and CC genotypes (8/161; 5.0%); in univariate analysis, the TT genotype was significantly associated with CV events (HR = 2.53; 95% CI = 1.16-5.51, p = 0.02). After adjustment for age, AHI, sex, smoking, diabetes, statin use, and BMI, the TT genotype remained a significant predictor (HR = 2.35; 95% CI = 1.02-5.42, p = 0.046). No events were found in patients with an absence of both OSA and the TT genotype (N = 30). The effect of the SNP was partially (16.2%) mediated by e-selectin levels. CONCLUSION: This is the first study to examine genetic variants as a risk factor for incident CVD in the context of OSA. Although these results are preliminary and in need of replication, it suggests that genetic markers may become useful in helping to guide precision clinical care.

Synthesis of ribavirin 1,2,3- and 1,2,4-triazolyl analogs with changes at the amide and cytotoxicity in breast cancer cell lines.

We report the synthesis and cytotoxicity in MCF-7 and MDA-MB-231 breast cancer cells of novel 1,2,3- and 1,2,4-triazolyl analogs of ribavirin. We modified ribavirin's carboxamide moiety to test the effects of lipophilic groups. 1-ß-D-Ribofuranosyl-1H-1,2,3-triazoles were prepared using Click Chemistry, whereas an unprecedented application of a prior 1,2,4-triazole ring synthesis was used for 1-ß-D-ribofuranosyl-1H-1,2,4-triazole analogs. Though cytotoxicity was mediocre and there was no correlation with lipophilicity, we discovered that a structurally similar concentrative nucleoside transporter 2 (CNT2) inhibitor was modestly cytotoxic (MCF-7 IC50 of 42 µM). These syntheses could be used to efficiently investigate variation in the nucleobase.

Stiffness and arthroscopic rotator cuff repair: a literature review.

Background and Objective: Tendon retear is the most common complication following rotator cuff repair surgery. Understanding the factors that are associated with greater risks of retear is important so surgeons can provide accurate prognostic information to patients. Advanced age and larger tear size have been shown to be associated with greater risk of retear at 6 months using multiple logistic regression analysis. Stiffness is the second most common complication, however recent evidence suggests that early postoperative stiffness may be associated with a more robust healing response. Thus, this paper aims to critically review the independent predictors of retear in rotator cuff repair patients. Methods: Literature review was conducted using electronic databases from their dates of inception. Key Content and Findings: There are multiple factors that affect rotator cuff repair integrity detailed in the literature. Tear size appeared to be the most important predictor of retear following rotator cuff repair. Postoperative stiffness at 6 and 12 weeks after surgery appears to be a factor associated with more intact repairs at 6 months. Shoulder stiffness tends to resolve within 6 months following the operation. This protective effect persists up to 5 years postoperatively. Conclusions: Shoulder stiffness may be an important protective factor against rotator cuff retear which requires further investigation from future studies. It is important to determine the relative importance of stiffness when compared to known important factors such as tear size with regards to its effect on rotator cuff repair integrity.

Describing inhibitor specificity for the amino acid transporter LAT1 from metainference simulations.

The human L-type amino acid transporter 1 (LAT1; SLC7A5) is a membrane transporter of amino acids, thyroid hormones, and drugs such as the Parkinson's disease drug levodopa (L-Dopa). LAT1 is found in the blood-brain barrier, testis, bone marrow, and placenta, and its dysregulation has been associated with various neurological diseases, such as autism and epilepsy, as well as cancer. In this study, we combine metainference molecular dynamics simulations, molecular docking, and experimental testing, to characterize LAT1-inhibitor interactions. We first conducted a series of molecular docking experiments to identify the most relevant interactions between LAT1's substrate-binding site and ligands, including both inhibitors and substrates. We then performed metainference molecular dynamics simulations using cryoelectron microscopy structures in different conformations of LAT1 with the electron density map as a spatial restraint, to explore the inherent heterogeneity in the structures. We analyzed the LAT1 substrate-binding site to map important LAT1-ligand interactions as well as newly described druggable pockets. Finally, this analysis guided the discovery of previously unknown LAT1 ligands using virtual screening and cellular uptake experiments. Our results improve our understanding of LAT1-inhibitor recognition, providing a framework for rational design of future lead compounds targeting this key drug target.

Tear Size and Stiffness Are Important Predictors of Retear: An Assessment of Factors Associated with Repair Integrity at 6 Months in 1,526 Rotator Cuff Repairs.

This study aimed to identify whether early postoperative shoulder stiffness is associated with improved healing following rotator cuff repair, and if so, how this factor might interact with other factors known to affect rotator cuff repair integrity. Methods: We conducted a retrospective analysis of prospectively collected data from 1,526 primary arthroscopic rotator cuff repairs. Six-week range of motion was assessed to determine shoulder stiffness, and repair integrity was evaluated at 6 months by ultrasound. Multiple logistic regression analysis was used to identify variables that affected retear, and receiver operating characteristic (ROC) curve analysis was used to evaluate predictive thresholds for retear. Results: Tear-size area was the most accurate predictor of retear (area under the curve [AUC] = 0.77; 95% confidence interval [CI] = 0.72 to 0.81), followed by 6-week passive external rotation (AUC = 0.67; 95% CI = 0.63 to 0.72), 6-week passive forward flexion (AUC = 0.67; 95% CI = 0.62 to 0.72), age (AUC = 0.65; 95% CI = 0.60 to 0.70), tear type (partial-thickness versus full-thickness) (AUC = 0.65; 95% CI = 0.61 to 0.69), and hospital type (public versus private) (AUC = 0.43; 95% CI = 0.37 to 0.49). Patients with smaller tears, reduced 6-week passive external rotation, reduced 6-week passive forward flexion, younger age, partial-thickness tears, and operations performed in a private day surgery or hospital setting were more likely to have an intact rotator cuff repair at 6 months. The AUC of this curve was 0.84 (95% CI = 0.80 to 0.87), which indicates that this combination of factors can accurately predict 84% of retears. Reduced range of motion at 6 weeks was associated with improved repair integrity for patients with tears of >1 to 6 cm2; however, this effect was less pronounced in tears of ≤1 cm2 or >6 cm2. Conclusions: Early postoperative stiffness following arthroscopic single-row, inverted-mattress rotator cuff repair at 6 weeks was associated with an intact repair at 6 months. The protective effects of postoperative stiffness and tear size were additive. The chance of retear in patients with a tear of ≤1 cm2 and external rotation of ≤27° at 6 weeks was 1%, while those with tears of >6 cm2 and external rotation of >27° had a 40% chance. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Secondary bile acids mediate high-fat diet-induced upregulation of R-spondin 3 and intestinal epithelial proliferation.

A high-fat diet (HFD) contributes to the increased incidence of colorectal cancer, but the mechanisms are unclear. We found that R-spondin 3 (Rspo3), a ligand for leucine-rich, repeat-containing GPCR 4 and 5 (LGR4 and LGR5), was the main subtype of R-spondins and was produced by myofibroblasts beneath the crypts in the intestine. HFD upregulated colonic Rspo3, LGR4, LGR5, and ß-catenin gene expression in specific pathogen-free rodents, but not in germ-free mice, and the upregulations were prevented by the bile acid (BA) binder cholestyramine or antibiotic treatment, indicating mediation by both BA and gut microbiota. Cholestyramine or antibiotic treatments prevented HFD-induced enrichment of members of the Lachnospiraceae and Rumincoccaceae, which can transform primary BA into secondary BA. Oral administration of deoxycholic acid (DCA), or inoculation of a combination of the BA deconjugator Lactobacillus plantarum and 7α-dehydroxylase-containing Clostridium scindens with an HFD to germ-free mice increased serum DCA and colonic Rspo3 mRNA levels, indicating that formation of secondary BA by gut microbiota is responsible for HFD-induced upregulation of Rspo3. In primary myofibroblasts, DCA increased Rspo3 mRNA via TGR5. Finally, we showed that cholestyramine or conditional deletion of Rspo3 prevented HFD- or DCA-induced intestinal proliferation. We conclude that secondary BA is responsible for HFD-induced upregulation of Rspo3, which, in turn, mediates HFD-induced intestinal epithelial proliferation.