Defatting of donor transplant livers during normothermic perfusion-a randomised clinical trial: study protocol for the DeFat study.

BACKGROUND: Liver disease is the third leading cause of premature death in the UK. Transplantation is the only successful treatment for end-stage liver disease but is limited by a shortage of suitable donor organs. As a result, up to 20% of patients on liver transplant waiting lists die before receiving a transplant. A third of donated livers are not suitable for transplant, often due to steatosis. Hepatic steatosis, which affects 33% of the UK population, is strongly associated with obesity, an increasing problem in the potential donor pool. We have recently tested defatting interventions during normothermic machine perfusion (NMP) in discarded steatotic human livers that were not transplanted. A combination of therapies including forskolin (NKH477) and L-carnitine to defat liver cells and lipoprotein apheresis filtration were investigated. These interventions resulted in functional improvement during perfusion and reduced the intrahepatocellular triglyceride (IHTG) content. We hypothesise that defatting during NMP will allow more steatotic livers to be transplanted with improved outcomes. METHODS: In the proposed multi-centre clinical trial, we will randomly assign 60 livers from donors with a high-risk of hepatic steatosis to either NMP alone or NMP with defatting interventions. We aim to test the safety and feasibility of the defatting intervention and will explore efficacy by comparing ex-situ and post-reperfusion liver function between the groups. The primary endpoint will be the proportion of livers that achieve predefined functional criteria during perfusion which indicate potential suitability for transplantation. These criteria reflect hepatic metabolism and injury and include lactate clearance, perfusate pH, glucose metabolism, bile composition, vascular flows and transaminase levels. Clinical secondary endpoints will include proportion of livers transplanted in the two arms, graft function; cell-free DNA (cfDNA) at follow-up visits; patient and graft survival; hospital and ITU stay; evidence of ischemia-reperfusion injury (IRI); non-anastomotic biliary strictures and recurrence of steatosis (determined on MRI at 6 months). DISCUSSION: This study explores ex-situ pharmacological optimisation of steatotic donor livers during NMP. If the intervention proves effective, it will allow the safe transplantation of livers that are currently very likely to be discarded, thereby reducing waiting list deaths. TRIAL REGISTRATION: ISRCTN ISRCTN14957538. Registered in October 2022.

LDHB contributes to the regulation of lactate levels and basal insulin secretion in human pancreatic ß cells.

Using 13C6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1H-13C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning ß cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and ß cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human ß cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in ß cells to maintain appropriate insulin release.

Bioconjugate based on cisplatin and bacterial exopolysaccharide with reduced side effects: A novel proposal for cancer treatment.

BACKGROUND: In the search for alternatives that attenuate the toxicity associated to oncologic treatment with cisplatin (CDDP) and considering the potential health-beneficial properties of exopolysaccharides (EPS) produced by lactic acid bacteria, it was aimed on this study to evaluate the cytotoxic, toxicologic and antitumoral efficacy of a bioconjugate based on CDDP and EPS, on the experimental tumor of sarcoma 180. METHODS: After the synthesis of the cis-[Pt(NH3)2(Cl)2] complex and of the conjugate containing Lactobacillus fermentum exopolysaccharide was tested both in vitro and in vivo for evaluating the acute toxicity. RESULTS: The antitumoral study was performed using mice transplanted with sarcoma 180. The bioconjugate showed low to medium cytotoxicity for the cell lines tested, as well moderated acute toxicity. After determining the LD50, the following experimental groups were established for the antitumor assay: Control (NaCl 0,9%), CDDP (1 mg/kg), EPS and bioconjugate composition (200 mg/kg). The bioconjugate promoted a 38% regression in tumor mass when compared to the control, and a regression of 41% when compared to CDDP. Liver histopathological analysis revealed discrete alterations in animals treated with (CDDP + EPS) when compared to control. The bioconjugate also minimized changes in the renal parenchyma resulting from the tumor. CONCLUSION: Our results indicate that when CDDP is associated with EPS, this composition was more biocompatible, showing itself as a potent chemotherapeutic agent and lower tissue toxicity.

Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of upper and lower limb nerve blocks.

BACKGROUND: Inconsistent nomenclature and anatomical descriptions of regional anesthetic techniques hinder scientific communication and engender confusion; this in turn has implications for research, education and clinical implementation of regional anesthesia. Having produced standardized nomenclature for abdominal wall, paraspinal and chest wall regional anesthetic techniques, we aimed to similarly do so for upper and lower limb peripheral nerve blocks. METHODS: We performed a three-round Delphi international consensus study to generate standardized names and anatomical descriptions of upper and lower limb regional anesthetic techniques. A long list of names and anatomical description of blocks of upper and lower extremities was produced by the members of the steering committee. Subsequently, two rounds of anonymized voting and commenting were followed by a third virtual round table to secure consensus for items that remained outstanding after the first and second rounds. As with previous methodology, strong consensus was defined as ≥75% agreement and weak consensus as 50%-74% agreement. RESULTS: A total of 94, 91 and 65 collaborators participated in the first, second and third rounds, respectively. We achieved strong consensus for 38 names and 33 anatomical descriptions, and weak consensus for five anatomical descriptions. We agreed on a template for naming peripheral nerve blocks based on the name of the nerve and the anatomical location of the blockade and identified several areas for future research. CONCLUSIONS: We achieved consensus on nomenclature and anatomical descriptions of regional anesthetic techniques for upper and lower limb nerve blocks, and recommend using this framework in clinical and academic practice. This should improve research, teaching and learning of regional anesthesia to eventually improve patient care.

The Current Role and Future Applications of Machine Perfusion in Liver Transplantation.

The relative paucity of donor livers suitable for transplantation has sparked innovations to preserve and recondition organs to expand the pool of transplantable organs. Currently, machine perfusion techniques have led to the improvement of the quality of marginal livers and to prolonged cold ischemia time and have allowed for the prediction of graft function through the analysis of the organ during perfusion, improving the rate of organ use. In the future, the implementation of organ modulation might expand the scope of machine perfusion beyond its current usage. The aim of this review was to provide an overview of the current clinical use of machine perfusion devices in liver transplantation and to provide a perspective for future clinical use, including therapeutic interventions in perfused donor liver grafts.

QUANTITATIVE ASSESSMENT OF AUTOMATED OPTICAL COHERENCE TOMOGRAPHY IMAGE ANALYSIS USING A HOME-BASED DEVICE FOR SELF-MONITORING NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To evaluate a prototype home optical coherence tomography device and automated analysis software for detection and quantification of retinal fluid relative to manual human grading in a cohort of patients with neovascular age-related macular degeneration. METHODS: Patients undergoing anti-vascular endothelial growth factor therapy were enrolled in this prospective observational study. In 136 optical coherence tomography scans from 70 patients using the prototype home optical coherence tomography device, fluid segmentation was performed using automated analysis software and compared with manual gradings across all retinal fluid types using receiver-operating characteristic curves. The Dice similarity coefficient was used to assess the accuracy of segmentations, and correlation of fluid areas quantified end point agreement. RESULTS: Fluid detection per B-scan had area under the receiver-operating characteristic curves of 0.95, 0.97, and 0.98 for intraretinal fluid, subretinal fluid, and subretinal pigment epithelium fluid, respectively. On a per volume basis, the values for intraretinal fluid, subretinal fluid, and subretinal pigment epithelium fluid were 0.997, 0.998, and 0.998, respectively. The average Dice similarity coefficient values across all B-scans were 0.64, 0.73, and 0.74, and the coefficients of determination were 0.81, 0.93, and 0.97 for intraretinal fluid, subretinal fluid, and subretinal pigment epithelium fluid, respectively. CONCLUSION: Home optical coherence tomography device images assessed using the automated analysis software showed excellent agreement to manual human grading.

Coexistence of flavum ligament ossification with diffuse idiopathic skeletal hyperostosis in the cervical spine: Review of literature and technical note starting from a rare case.

BACKGROUND: Cervical flavum ligament ossification (C-OLF) is very rare source of myeloradiculopathy. Less than 100 cases have been reported in modern English literature up to 2020. Association between C-OLF and Diffuse Idiopathic Skeletal Hyperostosis (DISH) at cervical level has never been described. METHODS: In this article we performed a systematic review about epidemiology, physiopathology, clinical and surgical management of C-OLF. Moreover, we research its possible association with other cervical spine ligament ossification and in particular with anterior longitudinal ligament ossification. We report a case of 73 years-old woman experiencing mild cervical myeloradiculopathy caused by C6-C7 C-OLF compression and coexistence of DISH at cervico-thoracic level. A brief technical note about intraoperative management of C-OLF has also been described. RESULT: Our research found 81 previous reported case of C-OLF. The coexistence of Posterior longitudinal ligament ossification has been reported in 21.3% of C-OLF case. Conversely, we reported the first case describing the association between DISH and C-OLF. Posterior surgical decompression is the only useful treatment providing good long-term functional outcome. Instrumentation should be tailored according to pre-operative findings. CONCLUSIONS: C-OLF is a rare source of myeloradiculopathy and it may coexists with DISH probably due to alteration in the cervical mechanical stress and tendency of bone formation in patients harboring coexistent ligament ossifications. According to our result, skip en-bloc microsurgical laminectomy is safe and less invasive method to avoid complication and to provide optimal cervical spinal cord and nerve decompression avoiding CSF-leak.

Predicting Early Allograft Function After Normothermic Machine Perfusion.

BACKGROUND: Normothermic ex situ liver perfusion is increasingly used to assess donor livers, but there remains a paucity of evidence regarding criteria upon which to base a viability assessment or criteria predicting early allograft function. METHODS: Perfusate variables from livers undergoing normothermic ex situ liver perfusion were analyzed to see which best predicted the Model for Early Allograft Function score. RESULTS: One hundred fifty-four of 203 perfused livers were transplanted following our previously defined criteria. These comprised 84/123 donation after circulatory death livers and 70/80 donation after brain death livers. Multivariable analysis suggested that 2-h alanine transaminase, 2-h lactate, 11 to 29 mmol supplementary bicarbonate in the first 4 h, and peak bile pH were associated with early allograft function as defined by the Model for Early Allograft Function score. Nonanastomotic biliary strictures occurred in 11% of transplants, predominantly affected first- and second-order ducts, despite selection based on bile glucose and pH. CONCLUSIONS: This work confirms the importance of perfusate alanine transaminase and lactate at 2-h, as well as the amount of supplementary bicarbonate required to keep the perfusate pH > 7.2, in the assessment of livers undergoing perfusion. It cautions against the use of lactate as a sole indicator of viability and also suggests a role for cholangiocyte function markers in predicting early allograft function.

Development of myelinating glia: An overview.

Myelin is essential to nervous system function, playing roles in saltatory conduction and trophic support. Oligodendrocytes (OLs) and Schwann cells (SCs) form myelin in the central and peripheral nervous systems respectively and follow different developmental paths. OLs are neural stem-cell derived and follow an intrinsic developmental program resulting in a largely irreversible differentiation state. During embryonic development, OL precursor cells (OPCs) are produced in distinct waves originating from different locations in the central nervous system, with a subset developing into myelinating OLs. OPCs remain evenly distributed throughout life, providing a population of responsive, multifunctional cells with the capacity to remyelinate after injury. SCs derive from the neural crest, are highly dependent on extrinsic signals, and have plastic differentiation states. SC precursors (SCPs) are produced in early embryonic nerve structures and differentiate into multipotent immature SCs (iSCs), which initiate radial sorting and differentiate into myelinating and non-myelinating SCs. Differentiated SCs retain the capacity to radically change phenotypes in response to external signals, including becoming repair SCs, which drive peripheral regeneration. While several transcription factors and myelin components are common between OLs and SCs, their differentiation mechanisms are highly distinct, owing to their unique lineages and their respective environments. In addition, both OLs and SCs respond to neuronal activity and regulate nervous system output in reciprocal manners, possibly through different pathways. Here, we outline their basic developmental programs, mechanisms regulating their differentiation, and recent advances in the field.

Systematic review, meta-analysis and single-centre experience of the diagnostic accuracy of intraoperative near-infrared indocyanine green-fluorescence in detecting pancreatic tumours.

BACKGROUND: During pancreatic resections assessing tumour boundaries and identifying the ideal resection margins can be challenging due to the associated pancreatic gland inflammation and texture. This is particularly true in the context of minimally invasive surgery, where there is a very limited or absent tactile feedback. Indocyanine green (ICG) fluorescence imaging can assist surgeons by simply providing valuable real-time intraoperative information at low cost with minimal side effects. This meta-analysis summarises the available evidence on the use of near-infrared fluorescence imaging with ICG for the intraoperative visualization of pancreatic tumours (PROSPERO ID: CRD42021247203). METHODS: MEDLINE, Embase, and Web Of Science electronic databases were searched to identify manuscripts where ICG was intravenously administered prior to or during pancreatic surgery and reporting the prevalence of pancreatic lesions visualised through fluorescence imaging. RESULTS: Six studies with 7 series' reporting data on 64 pancreatic lesions were included in the analysis. MINOR scores ranged from 6 to 10, with a median of 8. The most frequent indications were pancreatic adenocarcinoma and neuroendocrine tumours. In most cases (67.2%) ICG was administered during surgery. ICG fluorescence identified 48/64 lesions (75%) with 81.3% accuracy, 0.788 (95%CI 0.361-0.961) sensitivity, 1 (95%CI 0.072-1) specificity and positive predictive value of 0.982 (95%CI 0.532-1). In line with the literature, ICG fluorescence identified 5/6 (83.3%) of pancreatic lesions during robotic pancreatic resections performed at our Institution. CONCLUSION: This meta-analysis is the first summarising the results of ICG immunofluorescence in detecting pancreatic tumours during surgery, showing good accuracy. Additional research is needed to define optimal ICG administration strategies and fluorescence intensity cut-offs.

A Combined Conduit-Bioactive Hydrogel Approach for Regeneration of Transected Sciatic Nerves.

Transected peripheral nerve injury (PNI) affects the quality of life of patients, which leads to socioeconomic burden. Despite the existence of autografts and commercially available nerve guidance conduits (NGCs), the complexity of peripheral nerve regeneration requires further research in bioengineered NGCs to improve surgical outcomes. In this work, we introduce multidomain peptide (MDP) hydrogels, as intraluminal fillers, into electrospun poly(ε-caprolactone) (PCL) conduits to bridge 10 mm rat sciatic nerve defects. The efficacy of treatment groups was evaluated by electromyography and gait analysis to determine their electrical and motor recovery. We then studied the samples' histomorphometry with immunofluorescence staining and automatic axon counting/measurement software. Comparison with negative control group shows that PCL conduits filled with an anionic MDP may improve functional recovery 16 weeks postoperation, displaying higher amplitude of compound muscle action potential, greater gastrocnemius muscle weight retention, and earlier occurrence of flexion contracture. In contrast, PCL conduits filled with a cationic MDP showed the least degree of myelination and poor functional recovery. This phenomenon may be attributed to MDPs' difference in degradation time. Electrospun PCL conduits filled with an anionic MDP may become an attractive tissue engineering strategy for treating transected PNI when supplemented with other bioactive modifications.

Daam2 Regulates Myelin Structure and the Oligodendrocyte Actin Cytoskeleton through Rac1 and Gelsolin.

Myelin is essential to neuronal health and CNS function, and oligodendrocytes (OLs) undergo a complex process of cytoskeletal remodeling to form compact myelin sheaths. We previously discovered that a formin protein, Dishevelled associated activator of morphogenesis 2 (Daam2), suppresses OL differentiation through Wnt signaling; however, its role in cytoskeletal control remains unknown. To investigate this, we used OL-specific Daam2 conditional knockout (Daam2 cKO) mice of either sex and found myelin decompaction during an active period of myelination in postnatal development and motor coordination deficits in adulthood. Using primary OL cultures, we found Daam2-depleted OLs showed morphologic dysregulation during differentiation, suggesting that Daam2 regulates the OL cytoskeleton. In vivo screening identified the actin regulators Rac1 and Gelsolin as possible effectors in Daam2-deficient OL cytoskeletal regulation. Using gain-of-function and loss-of-function (LOF) experiments in primary OLs, we found that Rac1 and Gelsolin operate downstream of Daam2 in OL differentiation, with Gelsolin and Daam2 promoting and inhibiting membrane spreading during late differentiation, respectively. In vivo experiments using Daam2 cKO mice revealed increased protein levels of Gelsolin in the developing white matter with no change in RNA levels, suggesting that Daam2 acts in a posttranslational manner to suppress Gelsolin levels. In vitro biochemical studies show Daam2 induces Gelsolin ubiquitination and degradation in OLs. Together, our studies show Daam2 is essential for formation of functional myelin through modulation of Gelsolin levels to regulate the OL cytoskeleton. These findings further demonstrate the critical role of cytoskeletal dynamics in myelination and reveal novel avenues for treatment of a variety of white matter diseases.SIGNIFICANCE STATEMENT Proper myelin formation is essential to CNS function, and oligodendrocytes (OLs) require extensive changes in the actin cytoskeleton to form myelin sheaths. Here, we show that the formin protein Dishevelled associated activator of morphogenesis 2 (Daam2) is necessary for myelin compaction during development and motor learning in adulthood. Further, we demonstrate that Daam2 regulates OL differentiation and morphology through actin regulators Rac1 and Gelsolin. Lastly, we find that Daam2 may control myelin compaction by modulating the ubiquitination and degradation of Gelsolin through recruitment of the E3 ubiquitin ligase Nedd4. These findings reveal novel pathways for regulating myelin structure and function during white matter development.

Machine perfusion of the liver: applications in transplantation and beyond.

The shortage of donor livers considered suitable for transplantation has driven the development of novel methods for organ preservation and reconditioning. Machine perfusion techniques can improve the quality of marginal livers, extend the time for which they can be preserved and enable an objective assessment of their quality and viability. These benefits can help avoid the needless wastage of organs based on hypothetical concerns regarding quality. As machine perfusion techniques are gaining traction in clinical practice, attention has now shifted to their potential applications beyond transplantation. As well as providing an update on the current status of machine perfusion in clinical practice, this Perspective discusses how this technology is being used as a tool for therapeutic interventions including defatting of steatotic livers, immunomodulation and gene therapies.

Regional heterogeneity of astrocyte morphogenesis dictated by the formin protein, Daam2, modifies circuit function.

Astrocytes display extraordinary morphological complexity that is essential to support brain circuit development and function. Formin proteins are key regulators of the cytoskeleton; however, their role in astrocyte morphogenesis across diverse brain regions and neural circuits is unknown. Here, we show that loss of the formin protein Daam2 in astrocytes increases morphological complexity in the cortex and olfactory bulb, but elicits opposing effects on astrocytic calcium dynamics. These differential physiological effects result in increased excitatory synaptic activity in the cortex and increased inhibitory synaptic activity in the olfactory bulb, leading to altered olfactory behaviors. Proteomic profiling and immunoprecipitation experiments identify Slc4a4 as a binding partner of Daam2 in the cortex, and combined deletion of Daam2 and Slc4a4 restores the morphological alterations seen in Daam2 mutants. Our results reveal new mechanisms regulating astrocyte morphology and show that congruent changes in astrocyte morphology can differentially influence circuit function.

Modeling IKZF1 lesions in B-ALL reveals distinct chemosensitivity patterns and potential therapeutic vulnerabilities.

IKAROS family zinc finger 1 (IKZF1) alterations represent a diverse group of genetic lesions that are associated with an increased risk of relapse in B-cell acute lymphoblastic leukemia. Due to the heterogeneity of concomitant lesions, it remains unclear how IKZF1 abnormalities directly affect cell function and therapy resistance, and whether their consideration as a prognostic indicator is valuable in improving outcome. CRISPR/Cas9 strategies were used to engineer multiple panels of isogeneic lymphoid leukemia cell lines with a spectrum of IKZF1 lesions to measure changes in chemosensitivity, gene expression, cell cycle, and in vivo engraftment that can be linked to loss of IKAROS protein. IKZF1 knockout and heterozygous null cells displayed relative resistance to a number of common therapies for B-cell acute lymphoblastic leukemia, including dexamethasone, asparaginase, and daunorubicin. Transcription profiling revealed a stem/myeloid cell-like phenotype and JAK/STAT upregulation after IKAROS loss. A CRISPR homology-directed repair strategy was also used to knock-in the dominant-negative IK6 isoform into the endogenous locus, and a similar drug resistance profile, with the exception of retained dexamethasone sensitivity, was observed. Interestingly, IKZF1 knockout and IK6 knock-in cells both have significantly increased sensitivity to cytarabine, likely owing to marked downregulation of SAMHD1 after IKZF1 knockout. Both types of IKZF1 lesions decreased the survival time of xenograft mice, with higher numbers of circulating blasts and increased organ infiltration. Given these findings, exact specification of IKZF1 status in patients may be a beneficial addition to risk stratification and could inform therapy.

Noninvasive assessment of steatosis and viability of cold-stored human liver grafts by MRI.

PURPOSE: A shortage of suitable donor livers is driving increased use of higher risk livers for transplantation. However, current biomarkers are not sensitive and specific enough to predict posttransplant liver function. This is limiting the expansion of the donor pool. Therefore, better noninvasive tests are required to determine which livers will function following implantation and hence can be safely transplanted. This study assesses the temperature sensitivity of proton density fat fraction and relaxometry parameters and examines their potential for assessment of liver function ex vivo. METHODS: Six ex vivo human livers were scanned during static cold storage following normothermic machine perfusion. Proton density fat fraction, T1 , T2 , and T2∗ were measured repeatedly during cooling on ice. Temperature corrections were derived from these measurements for the parameters that showed significant variation with temperature. RESULTS: Strong linear temperature sensitivities were observed for proton density fat fraction (R2 = 0.61, P < .001) and T1 (R2 = 0.78, P < .001). Temperature correction according to a linear model reduced the coefficient of repeatability in these measurements by 41% and 36%, respectively. No temperature dependence was observed in T2 or T2∗ measurements. Comparing livers deemed functional and nonfunctional during normothermic machine perfusion by hemodynamic and biochemical criteria, T1 differed significantly: 516 ± 50 ms for functional versus 679 ± 60 ms for nonfunctional, P = .02. CONCLUSION: Temperature correction is essential for robust measurement of proton density fat fraction and T1 in cold-stored human livers. These parameters may provide a noninvasive measure of viability for transplantation.

Impact of Public Seating Design on Mobility and Independence of Older Adults.

Background:Mobility and independence of older adults are influenced by age-related capabilities and limitations, as well as environmental factors such as non-optimum design of public seating (e.g., inappropriate seat height, angle, and compressibility as well as armrests). This study was the first part of a multi-stage investigation of the impact of public seating on older adults. Method:One hundred and six older adults (aged 65 and over) completed an online survey regarding difficulties experienced with standing up from public seating (e.g. frequency; location; type of seating; effects). Results:A majority (59.4%) reported experiencing problems, with seat height the most common issue. Shopping malls, cafes and restaurants, doctor's offices, outdoor locations, and public toilets were the most common locations. Effects included inconvenience, embarrassment, discomfort, pain, and needing help from another person to stand. Discussion:Further research is needed to explore the locations and features of seating that can contribute to this problem.

Sperm cryopreservation during the SARS-CoV-2 pandemic.

PURPOSE: Sperm cryopreservation is fundamental in the management of patients undergoing gonadotoxic treatments. Concerns have risen in relation to SARS-CoV-2 and its potential for testicular involvement, since SARS-CoV-2-positive cryopreserved samples may have unknown effects on fertilization and embryo safety. This study therefore aimed to analyze the safety of sperm cryopreservation for cancer patients after the onset of the pandemic in Italy, through assessment of the risk of SARS-CoV-2 exposure and viral RNA testing of semen samples. METHODS: We recruited 10 cancer patients (mean age 30.5 ± 9.6 years) referred to our Sperm Bank during the Italian lockdown (from March 11th to May 4th 2020) who had not undergone a nasopharyngeal swab for SARS-CoV-2 testing. Patients were administered a questionnaire on their exposure to COVID-19, and semen samples were taken. Before cryopreservation, SARS-CoV-2 RNA was extracted from a 150 µl aliquot of seminal fluid in toto using QIAamp viral RNA kit (Qiagen) and amplified by a real time RT PCR system (RealStar SARS-CoV2 RT PCR, Altona Diagnostics) targeting the E and S genes. RESULTS: The questionnaire and medical interview revealed that all patients were asymptomatic and had had no previous contact with COVID-19 infected patients. All semen samples were negative for SARS-CoV-2 RNA. CONCLUSION: This preliminary assessment suggests that a thorough evaluation (especially in the setting of a multidisciplinary team) and molecular confirmation of the absence of SARS-CoV-2 in seminal fluid from asymptomatic cancer patients may assist in ensuring the safety of sperm cryopreservation.

Self-assembling multidomain peptide hydrogels accelerate peripheral nerve regeneration after crush injury.

Multidomain peptide (MDP) hydrogels are a class of self-assembling materials that have been shown to elicit beneficial responses for soft tissue regeneration. However, their capacity to promote nervous system regeneration remains unknown. The peripheral nervous system (PNS) substantially recovers after injury, partly due to the abundance of extracellular matrix (ECM) components in its basal lamina. However, severe peripheral nerve injuries that significantly damage the ECM continue to be a major clinical challenge as they occur at a high rate and can be extremely detrimental to patients' quality of life. In this study, a panel of eight MDPs were designed to contain various motifs mimicking extracellular matrix components and growth factors and successfully self-assembled into injectable, nanofibrous hydrogels. Using an in vitro screening system, various lysine based MDPs were found to enhance neurite outgrowth. To test their capacity to promote nerve regeneration in vivo, rat sciatic nerve crush injury was performed with MDP hydrogels injected directly into the injury sites. MDP hydrogels were found to enhance macrophage recruitment to the injury site and degrade efficiently over time. Rats that were injected with the MDP hydrogel K2 and laminin motif-containing MDPs K2-IIKDI and K2-IKVAV were found to have significantly accelerated functional recovery and remyelination compared to those injected with HBSS or other MDPs. These results demonstrate that MDPs enhance neurite outgrowth and promote a multicellular pro-regenerative response in peripheral nerve injury. This study provides important insights into the potential of MDPs as biomaterials for nerve regeneration and other clinical applications.