Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion.

JOURNAL/nrgr/04.03/01300535-202504000-00033/figure1/v/2024-07-06T104127Z/r/image-tiff Behavioral recovery using (viable) peripheral nerve allografts to repair ablation-type (segmental-loss) peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration. Furthermore, such peripheral nerve allografts undergo immunological rejection by the host immune system. In contrast, peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks, reduced immune responses, and many axons do not undergo Wallerian degeneration. The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study. We hypothesized that polyethylene glycol might have some immune-protective effects, but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery. We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion. Ablation-type sciatic nerve injuries in outbred Sprague-Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts, but peripheral nerve allografts were loose-sutured (loose-sutured polyethylene glycol) with an intentional gap of 1-2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons. Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts, animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively. Other morphological signs of rejection, such as collapsed Schwann cell basal lamina tubes, were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively. Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts. While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts, loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively. MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts, but MHCII expression was modestly lower compared to negative control at 21 days postoperatively. We conclude that, while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts, successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts, and produce recovery of sensory/motor functions and voluntary behaviors. Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

DNA-PAINT Probe Modifications Support High-Resolution Imaging with Shorter Binding Domains.

DNA-based Points Accumulation for Imaging in Nanoscale Topography (DNA-PAINT) is an effective super resolution microscopy technique, and its optimization is key to improve nanoscale detection. The state-of-the-art improvements that are at the base of this optimization have been first routinely validated on DNA nanostructure devices before being tested on biological samples. This allows researchers to finely tune DNA-PAINT imaging features in a more controllable in vitro environment. Dye-labeled oligonucleotide probes with short hybridization domains can expand DNA-PAINT's detection by targeting short nucleotide sequences and improving resolution, speed, and multiplexing. However, developing these probes is challenging as their brief bound state makes them difficult to capture under routine imaging conditions. To extend dwell binding times and promote duplex stability, we introduced structural and chemical modifications to our imager probes. The modifications included mini-hairpins and/or Bridged Nucleic Acids (BNA); both of which increase the thermomechanical stability of a DNA duplex. Using this approach we demonstrate DNA-PAINT imaging with approximately 5 nm resolution using a 4-nucleotide hybridization domain that is 43% shorter than previously reported probes. Imager probes with such short hybridization domains are key for improving detection on DNA nanostructure devices because they have the capability to target a larger number of binding domains per localization unit. This is essential for metrology applications such as Nucleic Acid Memory (NAM) where the information density is dependent on the binding site length. The selected imager probes reported here present imaging resolution equivalent to current state-of-the-art DNA-PAINT probes, creating a strategy to image shorter DNA domains for nanoscience and nanotechnology alike.

Amine-substituted heterocyclic thioamide Cu(I) and Ag(I) complexes as effective anticancer and antibacterial agents targeting the periplasm of E. coli bacteria.

Metal complexes showing dual activity against cancer and bacterial infections are currently the focus of significant interest for their potential in treating life-threatening diseases. Aiming to investigate the impact of ligand substituents on these bioactivity properties of Group 11 d10 metal complexes, we herein present a series of mononuclear Cu(I) and Ag(I) complexes featuring the bis-NH2-substituted heterocyclic thioamide dap2SH (=4,6-diaminopyrimidine-2-thione), namely [AgCl(dap2SH)(PPh3)2] (1), [CuBr(dap2SH)(PPh3)2] (2), [CuBr(dap2SH)(xantphos)] (3), [Ag(dap2S)(xantphos)] (4), and [Cu(dap2S)(xantphos)] (5) (xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene). Complexes were characterized by means of different physicochemical methods (i.e., single crystal X-ray diffraction as well as FTIR, NMR, UV-Vis and fluorescence spectroscopy), and studied in-vitro for their antibacterial and anticancer activity against a variety of bacterial strains and cancer cell lines. Complexes 1-3 effectively inhibited both Gram (+) and Gram (-) bacterial growth, while cellular uptake studies for the most potent complex 1 against E. coli bacteria revealed the accumulation of Ag(I) ions in the periplasm of the bacteria. A high anti-proliferative effect was observed for 1 and 5 against A549, MCF7 and PC3 cancer cell lines, with 1 being capable of inducing apoptosis in A549 cells, as suggested by flow cytometry analysis. DNA interaction studies revealed the capacity of 1 to intercalate between base-pairs of CT DNA. All complexes had a moderate-to-high capacity to scavenge free radicals preventing oxidative stress. Molecular docking calculations, in combination with the experimentally obtained data, provided insights for potential mechanisms of the bioactivity of the complexes.

Incidence of complications and functional outcomes following segmental femoral shaft fractures: a critical review of the literature.

BACKGROUND: Although segmental femoral shaft fractures (SFSF) are very challenging to manage, there has been no critical evaluation of the current practices and outcomes. The aim of this study is to evaluate their characteristics, management trends, outcomes, and complications. METHODS: A literature search was conducted via the SCOPUS, Embase (via SCOPUS) and MEDLINE (via PubMed) between 1995 and 2023. Studies were included if they reported patient demographics, mechanism of injury, classification of fractures, associated injuries, type of management, outcomes, and complications. EXCLUSION CRITERIA: only diaphyseal fractures were included and proximal and distal femoral fractures were excluded from this study. RESULTS: Overall, 22 studies met the inclusion criteria reporting on 313 patients. Mean age was 36.2 years with male-female ratio of 4.8 to 1. The majority were high-energy fractures secondary to road traffic accidents and 16% were open. The most commonly associated injuries included chest injury (27%) and lower leg fractures (24%). Treatment consisted of intramedullary nailing (IMN) (72%), plating (22%) or both combined (6%). Outcomes reported: good in 70%, fair in 10%, excellent in 19% and poor in 2% of cases. Mean time to union was 20 weeks. Complications are reported in 24% of cases, with most common delayed union (5%) and non-union (4%). CONCLUSION: SFSF are high-energy fractures occurring most commonly in young males, are open in 16% of cases and have significant associated injuries. In their overwhelming majority, IMN is the mainstay of treatment. The expected outcome is generally good in 70% of cases, although not devoid of complications in 24% of cases and patients must be aware of this during the consent process.

De novo gene synthesis by an antiviral reverse transcriptase.

Defense-associated reverse transcriptase (DRT) systems perform DNA synthesis to protect bacteria against viral infection, but the identities and functions of their DNA products remain largely unknown. Here we show that DRT2 systems encode an unprecedented immune pathway that involves de novo gene synthesis via rolling circle reverse transcription of a non-coding RNA (ncRNA). Programmed template jumping on the ncRNA generates a concatemeric cDNA, which becomes double-stranded upon viral infection. Remarkably, this DNA product constitutes a protein-coding, nearly endless ORF (neo) gene whose expression leads to potent cell growth arrest, thereby restricting the viral infection. Our work highlights an elegant expansion of genome coding potential through RNA-templated gene creation, and challenges conventional paradigms of genetic information encoded along the one-dimensional axis of genomic DNA.

Disentangling the detrimental effects of local from systemic adipose tissue dysfunction on articular cartilage in the knee.

OBJECTIVE: Obesity increases osteoarthritis (OA) risk due to adipose tissue dysfunction with associated metabolic syndrome and excess weight. Lipodystrophy syndromes exhibit systemic metabolic and inflammatory abnormalities similar to obesity without biomechanical overloading. Here, we used lipodystrophy mouse models to investigate the effects of systemic versus intra-articular adipose tissue dysfunction on the knee. METHODS: Intra-articular adipose tissue development was studied using reporter mice. Mice with selective lipodystrophy of intra-articular adipose tissue were generated by conditional knockout (cKO) of Bscl2 in Gdf5-lineage cells, and compared with congenital Bscl2 knockout (KO) mice with generalised lipodystrophy and associated systemic metabolic dysfunction. OA was induced by surgically destabilising the medial meniscus (DMM) and obesity by high-fat diet (HFD). Gene expression was analysed by quantitative RT-PCR and tissues were analysed histologically. RESULTS: The infrapatellar fat pad (IFP), in contrast to overlying subcutaneous adipose tissue, developed from a template established from the Gdf5-expressing joint interzone during late embryogenesis, and was populated shortly after birth by adipocytes stochastically arising from Pdgfrα+ Gdf5-lineage progenitors. While female Bscl2 KO mice with generalised lipodystrophy developed spontaneous knee cartilage damage, Bscl2 cKO mice with intra-articular lipodystrophy did not, despite synovial hyperplasia and inflammation of the residual IFP. Furthermore, male Bscl2 cKO mice showed no worse cartilage damage after DMM. However, female Bscl2 cKO mice with intra-articular lipodystrophy showed increased susceptibility to the cartilage-damaging effects of HFD-induced obesity. CONCLUSION: Our findings emphasise the prevalent role of systemic metabolic and inflammatory effects in impairing cartilage homeostasis, with a modulatory role for intra-articular adipose tissue.

A Vaping Cessation Text Message Program for Adolescent E-Cigarette Users: A Randomized Clinical Trial.

Importance: E-cigarettes are the most commonly used tobacco product among adolescents. Despite known harms of nicotine exposure among teens, there are no empirically tested vaping cessation interventions. Objective: To compare the effectiveness of a text message program for nicotine vaping cessation among adolescents with assessment-only control. Design, Setting, and Participants: A parallel, 2-group, double-blind, individually randomized clinical trial with follow-ups at 1 and 7 months after randomization was conducted from October 1, 2021, to October 18, 2023. Participants were recruited via social media ads; the intervention was delivered via text message; and assessments were completed online or by telephone. Eligible individuals were US residents aged 13 to 17 years who reported past 30-day e-cigarette use, were interested in quitting within 30 days, and owned a mobile phone with an active text message plan. To optimize study retention, all participants received monthly assessments via text message about e-cigarette use. Interventions: Assessment-only controls (n = 744) received only study retention text messages. Intervention participants (n = 759) also received an automated, interactive text message program for vaping cessation that delivers cognitive and behavioral coping skills training and social support. Main Outcomes and Measures: The primary outcome was self-reported 30-day point-prevalence abstinence from vaping at 7 months analyzed as intention-to-treat, with missingness coded as vaping. Results: Among n = 1503 adolescents randomized, average age was 16.4 (SD, 0.8) years. The sample was 50.6% female, 42.1% male, and 7.4% nonbinary/other; 10.2% Black/African American, 62.6% White, 18.5% multiracial, and 8.7% another race; 16.2% Hispanic; 42.5% sexual minority; and 76.2% vaped within 30 minutes of waking. The 7-month follow-up rate was 70.8%. Point-prevalence abstinence rates were 37.8% (95% CI, 34.4%-41.3%) among intervention participants and 28.0% (95% CI, 24.9%-31.3%) among control participants (relative risk, 1.35 [95% CI, 1.17-1.57]; P < .001). No baseline variables moderated the treatment-outcome relationship. There was no evidence that adolescents who quit vaping transitioned to combustible tobacco products. Conclusions and Relevance: A tailored, interactive text message intervention increased self-reported vaping cessation rates among adolescents recruited via social media channels. Trial Registration: ClinicalTrials.gov Identifier: NCT04919590.

Prevalence of Neurovascular Microemboli After Transcatheter Aortic Valve Replacement.

Background: Neurolotic sequelae after transcatheter aortic valve replacement (TAVR) can cause significant morbidity and mortality. Transcranial Doppler (TCD) imaging can show real-time high intensity transient signals (HITS), which reflect active microembolization. Although it is well known that intraprocedural microembolism occurs, it is not known if this embolic phenomenon continues in the postprocedural period. We investigated whether microemboli occur post-TAVR and whether we could determine any clinical, procedural, or echocardiographic predictors. Methods: We evaluated HITS in 51 consecutive patients undergoing unprotected TAVR with low-, intermediate-, or high-risk Society of Thoracic Surgeons score. Patients were excluded if they did not have temporal windows for insonation of the middle cerebral artery or if they were not willing to participate. Primary outcomes of HITS 24 hours post-TAVR were observed using a Philips iU22 TCD. TCD was performed at 3 time points (pre-, peri-, and post-TAVR) for each patient, before, during, and 24 hours postprocedure. Results: While no HITS were detected in any of the patients preoperatively, all patients had HITS during the procedure. Interestingly, 56.8% had HITS 24 hours post-TAVR. One patient with HITS post-TAVR had a stroke 48 hours after TAVR. Conclusion: We observed a high prevalence of microemboli 24 hours post-TAVR. None of the predictors for intraprocedural microembolism seemed to play an important role for post-TAVR microemboli.

Contrast-Induced Encephalopathy Following Transcatheter Aortic Valve Replacement: A Case Series.

Contrast-induced encephalopathy (CIE) is an idiopathic reaction following iodine-contrast dye administration in patients undergoing angiographic procedures. While it has been well-documented following coronary and carotid interventions, literature on CIE following transcatheter aortic valve replacement is limited. We report the multidisciplinary management of 3 patients with CIE following transcatheter aortic valve replacement.

Treatment of Transcatheter Aortic Valve Thrombosis: JACC Review Topic of the Week.

Transcatheter aortic valve (TAV) thrombosis may manifest as subclinical leaflet thrombosis (SLT) and clinical valve thrombosis. SLT is relatively common (10%-20%) after transcatheter aortic valve replacement, but clinical implications are uncertain. Clinical valve thrombosis is rare (1.2%) and associated with bioprosthetic valve failure, neurologic or thromboembolic events, heart failure, and death. Treatment for TAV thrombosis has been understudied. In principle, anticoagulation may prevent TAV thrombosis. Non-vitamin K oral anticoagulants, as compared to antiplatelet therapy, are associated with reduced incidence of SLT, although at the cost of higher bleeding and all-cause mortality risk. We present an overview of existing literature for management of TAV thrombosis and propose a rational treatment algorithm. Vitamin K antagonists or non-vitamin K oral anticoagulants are the cornerstone of antithrombotic treatment. In therapy-resistant or clinically unstable patients, ultraslow, low-dose infusion of thrombolytics seems effective and safe and may be preferred over redo-transcatheter aortic valve replacement or explant surgery.

Stabilizing the integrity of intestinal barrier to control arthritis.

With great interest, we have read the recent article "Expression of HIF1α in intestinal epithelium restricts arthritis inflammation by inhibiting RIPK3-induced cell death machinery" published by Lyu et al. in Annals of the Rheumatic Diseases. The authors pose that the expression of hypoxia-inducible factor 1 alpha in intestinal epithelial cells represents a crucial check point for the development of arthritis by impeding necroptosis of intestinal epithelial cells and safeguarding the intestinal barrier integrity. Previous studies suggest a potential mechanistic link between faulty intestinal barrier function and potentiation of arthritogenic immune cells. From this perspective, bolstering the intestinal barrier integrity arose as an attractive therapeutic strategy for rheumatoid arthritis.

Association of Body Mass Index and Parkinson Disease: A Bidirectional Mendelian Randomization Study.

BACKGROUND AND OBJECTIVES: The role of body mass index (BMI) in Parkinson disease (PD) is unclear. Based on the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in PD (Courage-PD) consortium, we used 2-sample Mendelian randomization (MR) to replicate a previously reported inverse association of genetically predicted BMI with PD and investigated whether findings were robust in analyses addressing the potential for survival and incidence-prevalence biases. We also examined whether the BMI-PD relation is bidirectional by performing a reverse MR. METHODS: We used summary statistics from a genome-wide association study (GWAS) to extract the association of 501 single-nucleotide polymorphisms (SNPs) with BMI and from the Courage-PD and international Parkinson Disease Genomics Consortium (iPDGC) to estimate their association with PD. Analyses are based on participants of European ancestry. We used the inverse-weighted method to compute odds ratios (ORIVW per 4.8 kg/m2 [95% CI]) of PD and additional pleiotropy robust methods. We performed analyses stratified by age, disease duration, and sex. For reverse MR, we used SNPs associated with PD from 2 iPDGC GWAS to assess the effect of genetic liability toward PD on BMI. RESULTS: Summary statistics for BMI are based on 806,834 participants (54% women). Summary statistics for PD are based on 8,919 (40% women) cases and 7,600 (55% women) controls from Courage-PD, and 19,438 (38% women) cases and 24,388 (51% women) controls from iPDGC. In Courage-PD, we found an inverse association between genetically predicted BMI and PD (ORIVW 0.82 [0.70-0.97], p = 0.012) without evidence for pleiotropy. This association tended to be stronger in younger participants (≤67 years, ORIVW 0.71 [0.55-0.92]) and cases with shorter disease duration (≤7 years, ORIVW 0.75 [0.62-0.91]). In pooled Courage-PD + iPDGC analyses, the association was stronger in women (ORIVW 0.85 [0.74-0.99], p = 0.032) than men (ORIVW 0.92 [0.80-1.04], p = 0.18), but the interaction was not statistically significant (p-interaction = 0.48). In reverse MR, there was evidence for pleiotropy, but pleiotropy robust methods showed a significant inverse association. DISCUSSION: Using an independent data set (Courage-PD), we replicate an inverse association of genetically predicted BMI with PD, not explained by survival or incidence-prevalence biases. Moreover, reverse MR analyses support an inverse association between genetic liability toward PD and BMI, in favor of a bidirectional relation.

The role of borderline personality disorder traits in predicting longitudinal variability of major depressive symptoms among a sample of depressed adults.

BACKGROUND: Major depressive disorder (MDD) and borderline personality disorder (BPD) often co-occur, with 20 % of adults with MDD meeting criteria for BPD. While MDD is typically diagnosed by symptoms persisting for several weeks, research suggests a dynamic pattern of symptom changes occurring over shorter durations. Given the diagnostic focus on affective states in MDD and BPD, with BPD characterized by instability, we expected heightened instability of MDD symptoms among depressed adults with BPD traits. The current study examined whether BPD symptoms predicted instability in depression symptoms, measured by ecological momentary assessments (EMAs). METHODS: The sample included 207 adults with MDD (76 % White, 82 % women) recruited from across the United States. At the start of the study, participants completed a battery of mental health screens including BPD severity and neuroticism. Participants completed EMAs tracking their depression symptoms three times a day over a 90-day period. RESULTS: Using self-report scores assessing borderline personality disorder (BPD) traits along with neuroticism scores and sociodemographic data, Bayesian and frequentist linear regression models consistently indicated that BPD severity was not associated with depression symptom change through time. LIMITATIONS: Diagnostic sensitivity and specificity may be restricted by use of a self-report screening tool for capturing BPD severity. Additionally, this clinical sample of depressed adults lacks a comparison group to determine whether subclinical depressive symptoms present differently among individuals with BPD only. CONCLUSIONS: The unexpected findings shed light on the interplay between these disorders, emphasizing the need for further research to understand their association.

Risk Factors of Ischemic Stroke in Patients With Atrial Fibrillation After Transcatheter Aortic Valve Implantation from the Randomized ENVISAGE-TAVI AF Trial.

In patients with prevalent or incident atrial fibrillation (AF) after successful transcatheter aortic valve implantation (TAVI) enrolled in the EdoxabaN Versus standard of care and theIr effectS on clinical outcomes in pAtients havinG undergonE Transcatheter Aortic Valve Implantation - in Atrial Fibrillation (ENVISAGE-TAVI AF) trial, the incidence of ischemic stroke (IS) and any stroke was numerically less in the edoxaban group than in the vitamin K antagonist (VKA) group. The present study aimed to identify risk factors associated with IS in an on-treatment subanalysis in patients from ENVISAGE-TAVI AF who received ≥1 dose of edoxaban or VKA. Baseline patient characteristics were compared in patients with and those without IS. Numerical variables were compared using a 1-way analysis of variance; categorical variables were compared using Fisher's exact test. Stepwise Cox regression determined patient characteristics associated with the first IS event. Of 1,377 patients, 41 (3.0%) experienced an IS, and 1,336 (97.0%) did not; baseline demographics and clinical characteristics were well balanced between groups. Most ISs occurred within 180 days of TAVI for edoxaban (57.9%) and VKA (68.2%). The rate of IS was 2.0/100 person-years for edoxaban versus 2.7/100 person-years for VKA. Independently associated with IS were history of systemic embolic events (hazard ratio 2.96, 95% confidence interval 1.26 to 7.00, p = 0.01) and pre-TAVI use of VKAs (hazard ratio 2.17, 95% confidence interval 1.12 to 4.20, p = 0.02). In conclusion, although the overall incidence of IS was small for patients with AF on edoxaban or VKA after successful TAVI, patients with a history of systemic embolic events or pre-TAVI use of VKAs may be at greater risk of IS after TAVI.