Bicuspid aortic valve (BAV) is the most frequent congenital cardiac abnormality leading to premature aortic valve apparatus dysfunction and is often associated with aortopathy. Therefore, current guidelines recommend a surgical aortic valve replacement (SAVR), even if many patients are deemed inoperable owing to their comorbidities and require alternatives such as transcatheter aortic valve replacement (TAVR). However, BAV variations remain challenging for procedural success. Therefore, the latest development in different imaging modalities  allows in-depth analysis for preprocedural risk stratification, follow up, and patient selection. Furthermore, we shed light on the latest developments in pre- and periprocedural fusion imaging as well as on current and future treatment options. The bicuspid aortic valve (BAV) is the most common congenital anomaly in adults. The frequency of this congenital aortic valve defect is given as approximately 1–2% in the total population, whereby regional differences need to be taken into consideration . To dateBAV leads to an accelerated damage of the valve apparatus, mostly beginning at a younger age and resulting in a more rapid severity progression than in TAV. Furthermore, BAV is commonly associated with aortic pathologies  and, therefore, a larger diameter of the ascending aorta as compared with the normal population with TAV. This thoracic aortic dilation is detected in approximately 40% of patients . The dilAlthough the current guidelines recommend a surgical aortic valve replacement (SAVR) for BAV, there are patients who are deemed inoperable owing to their comorbidities and require alternatives such as transcatheter aortic valve replacement (TAVR). Due to the challenging large anatomical variety in BAV, asymmetric calcifications, coronary anomalies, and associated aortopathies, multimodal imaging is pivotal for adequate patient selection and risk stratification concerning different treatment approaches. Therefore, we reviewed the role of different imaging tools for the diagnosis and treatment in this specific heterogeneous disease as well as current and future treatment options.Different imaging modalities are of importance in the diagnosis of BAV and possible complications. Echocardiography is the recommended imaging method of choice to visualize the valve anatomy and function. Aortic stenosis (AS) is observed more frequently in BAV than aortic regurgitation. An initial assessment by transthoracic echocardiography (TTE) based on peak jet velocity, mean transvalvular gradient, and effective orifice area measured according to the continuity equation is recommended. A subgroup may reveal severe AS with a tight valve area, but low transvalvular gradient. This might be associated with impaired left ventricular function or reduced stroke volume in a highly hypertrophied left ventricle of restrictive cardiomyopathy. Moreover, BAV is often combined with relevant aortic regurgitation. Its assessment relies on color, continuous, and pulsed wave Doppler accompanied with the left ventricular function. In some cases, TTE cannot sufficiently determine the direction of the aortic valve insufficiency jet in the longitudinal axis view  and its origin in the short axis view   Figure . The bicAccording to class I recommendations, cardiovascular magnetic resonance (CMR) should be used to determine the backflow volume if echocardiographic measurements are ambiguous . The difPrecise imaging examinations are of importance concerning the planning before interventional or surgical intervention in order to prevent severe complications such as prosthesis dislocation, annulus rupture, and severe paravalvular leakage. According to the current guidelines, MSCT is the preferred imaging tool for assessing the anatomy and dimensions of the aortic root, size, and shape of the aortic valve annulus; its distance from the coronary ostia; the distribution of calcifications; and the number of aortic valve leaflets. 3D-TEE can be used to determine aortic valve annulus dimensions, but is more operator and image quality dependent than MSCT . CompareAn 80-fold higher risk of aneurysms compared with the normal population could be demonstrated where the ascending aorta is affected in 60–70% of the cases . When meThe most important clinical decision is the optimal time for SAVR or TAVR. The maximum aortic diameter, the presence of aortic risk factors such as connective tissue disorders, and the presence of surgical risk factors  and accompanying indications such as aortic valve stenosis or insufficiency must be taken into account.Surgical treatment consists of aortic valve replacement using a biological or mechanical prosthetic heart valve. The selection of the heart valve prosthesis  fundamentally depends on the age of the patient and some other factors, and should be determined in a detailed patient informed consent before the planned operation . CurrentTAVR is well known to be the treatment option of choice in inoperable and high-risk patients, and currently even shows favorable outcome in intermediate and low-risk cohorts with TAV ,19,20. ULooking into the limited data, both balloon and self-expandable prostheses can be implanted successfully in selected BAV anatomies. However, a higher rate of more than mild perivalvular leak was found among patients treated with self-expandable valves . A higheHowever, new-generation transcatheter valves significantly improved the outcomes of TAVR in BAV in concerns of peri-procedural complications and early- to mid-term outcomes ,28,29. NThe number of TAVR procedures is expected to increase significantly in the following years. Improving efficacy will become essential for experienced operators in high volume centres, while less experienced operators will require in-depth training. Hereby, especially the BAV morphologies will remain challenging and require accurate pre- and peri-procedural work up. An accurate automated detection of aortic root dimensions might not only increase efficiency, but also reduce operator variability and the impact of the experience of the operator on sizing.Currently, there are two approaches described based on preprocedural MSCT data. Astudillo et al. described a deep learning method detecting the aortic annulus automatically and comparing to a control group that performed sizing manually. The automatically obtained device size selection was fast, accurate, and reproducible . AnotherNext-generation of real-time fusion of echocardiography and fluoroscopy enables a patient-specific segmented 3D heart model, which is feasible for any structural heart disease interventions. On the basis of a high-quality 3D TEE image of the aortic valve and its surrounding structured and a successful ECG-gated segmentation, a patient-specific 3D heart model can be obtained. As 3D TEE annulus measurements are comparable with MSCT in selected patients , automated sizing may be performed intra-procedurally . This apIn order to improve communication among the interventionalists and the understanding of 3D spatial orientation the application of holography for imaging was recently introduced. Holographic images allow a real-time visualization of a 3D-patient-specific dataset based on MSCT  and/or CMR data  floating in the air during the procedure in front of the interventionalists, enabling an intuitive and interactive display of the complex anatomy. Rymuza et al. describe its use in TAVR during a BAV anatomy type I L/R, facilitating the navigation and implantation of the valve prosthesis. Further studies are needed to evaluate its impact, for example, on the procedure-related parameters  ,35,36,373D-printing of the heart is a relatively new tool with high potential in planning complex surgical and transcatheter-based interventions, especially in congenital heart diseases . It is aTemporal trends and outcomes of transcatheter versus surgical aortic valve replacement in BAV revealed similar results on complications and outcomes . HoweverTricuspidization, as a technique of turning a bicuspid into a tricuspid valve, is a novel technique, agitating enhanced attention in surgical repair for adults ,48 and TIt must be pronounced that TAVR for BAV-related pure aortic regurgitation is not mentioned in the current guidelines and was listed as a contraindication before. However, there are several high-risk patients who cannot undergo surgical treatment. Off-label TAVR in pure aortic regurgitation has to face important challenges like necessary oversizing for anchoring without calcium; the associated risk of dislocation, annular rupture, and PVL; as well as frequently observed too large anatomies for current available TAVR devices. However, TAVR is likely to be established as an applicable alternative treatment with new dedicated devices in time . Figure Multimodal imaging in bicuspid aortic valve is essential for diagnosis and treatment of the progression of valve dysfunction and associated aortopathy. Besides the optimal time of surgical intervention, TAVR as an alternative treatment will gain more importance as it expands to low-risk patients and will include bicuspid aortic valve pathologies and new treatment strategies. Advanced pre-procedural fusion imaging tools may strengthen diagnostic accuracy and support best treatment strategies in complex anatomies.


Fungi) and fungus-like organisms  constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.True fungi ( Tree of Life , whereas about 0.7% represent Eumycetozoa and other groups of slime molds in the Amoebozoa (supergroup Amorphea), and another 0.7% the Oomycota in the Straminipila  or in the form of budding cells (yeast-like), reproducing via meiotic and/or mitotic spores. The fungal lifestyle evolved several times independently in the ife Fig. . The majFungi in the broad sense are ubiquitous in terrestrial, freshwater and marine ecosystems  cells, or plasmodia in slime molds, is usually cryptic, exhibiting little useful diagnostic information, except for classification attempts based on fungal cultures Nobles . In contDue to the heterogeneity of approaches to fungal taxonomy and the complexity of lineage-dependent evolutionary processes, there are no simple strategies to unambiguously identify fungi  or a false chanterelle (Hygrophoropsis aurantiaca), two unrelated species in different fungal orders. Once verified that the query taxon is a true chanterelle, precision would determine the exact species, as Cantharellus cibarius s.lat. Represents several more narrowly defined taxa  to thousands (multi-locus) to hundreds of thousands or more (phylogenomics) of sites. However, even with molecular data, difficulties arise from a lack of understanding of evolutionary processes, which are not always discernible in a phylogeny. For instance, recently emerging species may not resolve through reciprocal monophyly , support and concordance  and/or imagery, including digitized type material in repositories, such as nts Ryan , 2018 orInternational Sequence Database Collaboration (INSDC). The AJOM fungal notes series publishes new collections of known species with sequence data  to only higher taxa  should be avoided, unless this is the desired level of precision, justified by the objectives and underlying assumptions, or in environmental metabarcoding when no close relatives have been sequenced , and there is usually no consultation with taxonomic expertise. Another issue is the habit of citing sequence accession numbers as “sources” of identifications, while ignoring the underlying taxonomic work that let to the deposition of these valuable reference sequences in the first place. Looking up and citing these works is an important step in quality filtering of reference sequences and to some extent can replace taxonomic expertise when assessing results of DNA-based identifications. In environmental metabarcoding approaches, taxonomic expertise is unfortunately largely fruitless due to the absence of physical voucher specimens. Also, since metabarcoding typically encompasses a broad diversity of higher taxa . The accessibility of reference material, both physically and virtually, is crucial in this process. Ideally, a broad array of characters needs to be quantitatively analyzed to determine those most effective for identification  common ancestor (LCA) analysis in analytical packages, such as MEGAN, QIIME and BASTA  as the highest level of precision, even if the underlying data would allow an identification to species. Excluding all undetermined sequences, the best hits would include the genus names Trametes, Lenzites and Leiotrametes and hence return the family Polyporaceae as highest level of precision. Curated databases, such as UNITE permit the use of the species hypothesis identifier as highest level of precision, but this is cumbersome in the interpretation of massive amounts of data.A common misconception in DNA barcoding is the assumption that existing reference data provide a definitive answer, either in species identification or to establish whether a taxon is new. Such an approach will fail when reference data are incomplete or sequences are improperly labeled , plant or human/animal pathogens  or other fungi  including slime molds. For these, secondary barcoding markers, such as the intergenic spacer (IGS), β-tubulin II (TUB2), DNA-directed RNA polymerase II largest (RPB1) and second largest (RPB2) subunits, translational elongation factor 1α (TEF1), DNA topoisomerase I (TOP1), phosphoglycerate kinase (PGK), and cytochrome c oxidase subunit I (COX1) and subunit II (COX2), have been proposed  cistron, including the ITS region, particularly when producing non-homologous discrete ITS variants, as this may result in conflicting molecular identifications. Intragenomic ITS variation is well-documented for bacteria, plants and animals  stochastic point mutations resulting from DNA replication errors during cell division, (2) recombination through hybridization and introgression , which display high intragenomic rDNA variation  to over 1000 bases  may vary from less than 400 , species hypotheses delimited at 98.5% in UNITE include sequences from type material of several to numerous different species , (1) Nmatches / Ntotal pairwise alignment length minus indels (gap-excluded identity), and (3) Nmatches / Ntotal pairwise alignment length minus indel groups (gap-compressed identity). BLAST identity considers individual indels as mismatches and hence results in lower similarity values than the other two approaches for a given sequence pair. It is also more sensitive to homopolymer-based sequencing errors in the query reads and affected by improper trimming of low-quality terminal portions of reference sequences  NEven so, BLAST is the most commonly employed read mapping technique, either against a primary sequence repository, such as GenBank or against curated or otherwise specialized databases, such as UNITE. Notably, reported problems can largely be solved by increasing the quality and representativity of reference databases, in particular correct sequence labeling, and by adding a verification step . Up to the recent past, OTU clustering was the only viable approach to achieve this goal. However, phylogenetic binning is now possible through massive parallel computing on large clusters  taxonomic approach seems most effective, adjusted to the group under study and combining molecular and phenotype data. In many groups, single-marker DNA barcoding may suffice, whereas more complex taxa require a combination of primary and secondary barcoding markers or multi-marker approaches. Phylogenomics may be employed to resolve particularly difficult species complexes, but this approach demands large computational and personal resources and is currently limited to exemplar case studies.The phenotype remains an integrative component of fungal taxonomy, encompassing also data derived from cultures and other sources. Taxonomists will continue to describe new species in the absence of molecular data, in groups where this approach is justified. However, phenotypic data should be thoroughly analyzed before establishing new species by any method. If the material would allow the generation of molecular data but the methodology to do so is not available, then collaboration to produce such data is recommended. In general, the goal remains to document all fungi with molecular data. Phenotypic data are of particular importance when assessing the status of phylogenetically distinct clades through integrative taxonomy. In such cases, quantitative analysis of structured phenotype matrices should be implemented to assess phenotypic variation in a phylogenetic context, which will then also allow the detection of reliable diagnostic characters.On a molecular level, ITS remains the universal fungal barcode marker to initially identify phylogenetic lineages. It can thus be considered a first diagnosis. Where ITS does not suffice to discriminate between species, secondary barcoding markers or multi-locus approaches need to be employed to achieve the desired level of precision and accuracy. How individual markers resolve species is determined by context, and feasibility of particular markers should not be uncritically transferred from one taxonomic group to another but instead empirically explored for each taxon. ITS will likely remain the marker of choice for fungal metabarcoding studies, although long-read approaches or the addition of secondary barcoding markers will improve accuracy and precision. However, metabarcoding approaches should move away from OTU clustering and BLAST mapping exercises and instead implement phylogenetic methods, such as read placement (phylogenetic binning).Current issues arising with DNA barcoding of fungi are not primarily due to conceptual limitations of the approach but due to shortcomings of reference databases, including incompleteness in terms of taxonomic coverage, lack of properly documented genetic diversity, and inaccuracy of sequence labels. Major efforts must therefore be directed at further improving these resources, particularly the continued and critical revision of existing data to achieve high quality labels.


Staphylococcus aureus was detected in his synovial fluid culture, confirming the diagnosis of prepatellar septic bursitis. Prepatellar bursitis is well known as housemaid's knee, which is caused by inflammation of the prepatellar bursa among people who spend long periods of time kneeling such as housemaids, clergy, and gardeners.An 83-year-old Japanese tatami craftsman with underlying diabetes mellites who complained of severe pain and feeling of warmth in his right knee, with mild chills. Fluid accumulation was seen in his prepatellar bursa and  When evaluating a patient with knee swelling, a physician must consider whether the swelling is attributed to mono- or polyarticular pathology; this is also essential to the differential diagnosis of intra-articular or extra-articular soft tissue infection . PrepateAn 83-year-old male Japanese tatami craftsman with a history of diabetes mellitus presented to our emergency room with complaints of severe pain and warmth in the right knee, accompanied by mild chills [Staphylococcus aureus was detected in the synovial fluid culture, and the patient was hospitalized. First-generation cephem antibiotics were intravenously administered, leading to full recovery without sequelae.Fluid aspiration was performed, S. aureus is the primary causative organism in more than 80% of septic bursitis cases confirmed based on bacterial culture findings [Herein, we report the case of an elderly patient whose diagnosis of housemaid’s knee was delayed and who fully recovered after hospitalization and intravenous antibiotic administration. The main symptoms typically include pain, peribursal erythema, and warmth. Fever only occurs in 40-44% of cases . Gram stfindings ,7. For sfindings . We initfindings , confirmfindings , and faiThe clinically relevant message pertaining to this case is that when a patient who could be a candidate for housemaid’s knee presents with knee swelling, aspiration and culture are advisable to ascertain the characteristics of the fluid and arrive at the appropriate diagnosis. However, many physicians often diagnose such patients with pseudogout because they fail to perform said test. We believe that this is a fairly common pitfall when encountering mono-arthritis and fever symptoms in elderly patients.


However, new evidence also suggested that, paradoxically, elevated adiponectin levels can be associated with induction or existence of some pathologies.This topic collection focuses on adiponectin, one of the major adipokines. Adiponectin has been first described as a beneficial cytokine exhibiting insulin-sensitizing, anti-inflammatory, anti-atherogenic activities, and even anti-cancer properties. Numerous We strongly believe that research and medical communities interested in adiponectin will benefit from this updated discussion tackling the multifaceted nature of this protein and the challenges associated with a potential pharmaceutical development. This collection of peer-reviewed articles highlights the complexity of adiponectin biology, focusing on different diseases and/or sites of action, including cardiovascular disease, neurological disorders, and cancer development. Several reviews explore the utility of adiponectin as biomarker and biotarget as well as discuss strategies to rebalance adiponectin levels using novel pharmacological entities.Liu et al. “Examining the Potential of Developing and Implementing Use of Adiponectin-Targeted Therapeutics for Metabolic and Cardiovascular Diseases “ describes the physiological effects of adiponectin in cardiac tissue and potential impact of this adipokine in cardiovascular diseases. Furthermore, the authors suggest the use of adiponectin as a biomarker and a new tool for the detection and management of cardiovascular pathologies. Along these lines, a possibility to alleviate adiponectin deficiency in cardiac pathologies by employing adiponectin receptor agonists  is discussed.Adiponectin action is greatly impaired in cardiovascular diseases due to the reduced bioavailability and/or target tissue resistance. Consequently, the development of strategies to counteract hypoadiponectinemia in these pathologies is of great interest. The review of Maimaituxun et al. in the article “Levels of Adiponectin Expression in Peri-Renal and Subcutaneous Adipose Tissue and Its Determinants in Human Biopsied Samples” address the role of perirenal fat adipocytokines, especially adiponectin, in kidney pathologies. The authors evaluated adiponectin expression in perirenal adipose tissue (RAT), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) in urological surgery patients. Levels of adiponectin mRNA in RAT were found to be negatively correlated with remote fat mass in SAT and VAT, and with local fat mass in RAT, while levels of adiponectin in SAT were not associated with RAT volume. The authors discuss a possible role of RAT adiponectin and RAT volume in kidney function as well as in local and systemic inflammation.Epidemiological studies suggest that excessive perirenal fat increases the risk of cardiometabolic risk, hypertension, and cardiovascular disease. Bloemer et al. in the paper “Adiponectin Knockout Mice Display Cognitive and Synaptic Deficits” support an important role of adiponectin in brain functionality. Using adiponectin knockout mice, the authors demonstrated that adiponectin deficiency impairs synaptic processes and cognitive function. Most importantly, the knockout animals exhibited cognitive deficits, reduced basal synaptic transmission, increased presynaptic release probability, impaired synaptic plasticity, and altered glutamatergic receptor levels.Growing evidences suggest a protective role of adiponectin in several brain disorders including Alzheimer's disease, stroke, and depression. Although adiponectin receptors, AdipoR1 and AdipoR2, are widely distributed in various brain regions, the involvement of adiponectin in specific brain activities is not well-understood. The results presented by Waragai et al. in their article “Adiponectin Paradox in Alzheimer's Disease; Relevance to Amyloidogenic Evolvability” focus on the adiponectin paradox in Alzheimer's disease (AD) and discuss potential mechanisms involved. It is suggested that adiponectin might be involved in the stimulation of the amyloidogenic evolvability in reproductive stages, which may later manifest as AD by the antagonistic pleiotropy during aging. The authors also speculate on the potential links between the adiponectin paradox in AD and similar unusual adiponectin effects seen in other advanced age diseases such as chronic heart failure and chronic kidney disease.In the nervous system adiponectin appears to display both beneficial and toxic effects. Indeed, some studies performed in cellular and animal models reported a neuroprotective role of adiponectin, while others show a correlation between adiponectin, cognitive decline and severity of amyloid accumulation in elder population. Naimo et al. ‘Interfering Role of ERα on Adiponectin Action in Breast Cancer” discusses the role of adiponectin in breast cancer depending on estrogen receptor alpha (ERα) status. The authors argue that in obese patients, adiponectin may, paradoxically, act as a growth enhancer for ERα-positive breast cancer cells. Based on in vitro and in vivo evidence, this response could be related to ERα signaling overriding the inhibitory action of adiponectin. In contrast, in the absence of ERα, adiponectin may exhibit anti-neoplastic activities. The molecular mechanisms underlying the adiponectin/ERα interface are discussed in detail.Numerous studies highlighted the potential role of adiponectin in cancer development and progression. Especially, clinical data indicate that low adiponectin levels are associated with increased risk and more aggressive phenotype in breast cancer, while higher levels might have a protective effect. However, experimental data appear to suggest a more complex situation. The review of Xiang et al. and its addendum “Metabolic Syndrome, and Particularly the Hypertriglyceridemic-Waist Phenotype, Increases Breast Cancer Risk, and Adiponectin Is a Potential Mechanism: A Case–Control Study in Chinese Women” provides an interesting analysis suggesting that low adiponectin levels in conjunction with metabolic syndrome, especially the hyperglyceridemic waist phenotype, can be regarded as a strong predictor of breast cancer in Chinese women.A large case-control clinical study presented by Otvos “Potential Adiponectin Receptor Response Modifier Therapeutics” details currently tested peptide-based adiponectin replacement drug leads as well as discusses pharmaceutical potentials of small molecule therapies. The author analyzes advantages and difficulties in the reliability and readout of the in vitro measures and the wealth of in vivo models that make comparison of the various drug classes complicated. Alternative approaches to direct adiponectin signaling control that use adiponectin-upregulating strategies but offer relatively limited success compared to direct receptor agonists are also evaluated.The compelling experimental and clinical evidence strongly supports the efforts to develop clinically viable compounds targeting adiponectin signaling in human pathologies. Due to pharmacological disadvantages of the intact adiponectin protein, potential hypoadiponectinemia treatments focus on the use of peptidic, and small molecule agonists of the adiponectin receptor. A comprehensive review by ES and TF wrote and edited the editorial.ES serves as Senior Advisor for Allysta Pharmaceuticals, a company developing adiponectin-based therapeutics. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest


Nascent gestalt synapses are constantly formed as AMPA receptor-silent synapses which are the substrates for critical period plasticity. Experience drives the unsilencing and stabilization of gestalt synapses, as well as synapse pruning. This maturation process changes synapse patterning and consequently the functional architecture of cortical excitatory networks. Ocular dominance plasticity (ODP) in the primary visual cortex (V1) is an established experimental model for cortical plasticity. While converging evidence indicates that the start of the critical period for ODP is marked by the maturation of local inhibitory circuits, recent results support our model that critical periods end through the progressive maturation of gestalt synapses. The cooperative yet opposing function of two postsynaptic signaling scaffolds of excitatory synapses, PSD-93 and PSD-95, governs the maturation of gestalt synapses. Without those proteins, networks do not progress far beyond their innate functionality, resulting in rather impaired perception. While cortical networks remain malleable throughout life, the cellular mechanisms and the scope of critical period and adult plasticity differ. Critical period ODP is initiated with the depression of deprived eye responses in V1, whereas adult ODP is characterized by an initial increase in non-deprived eye responses. Our model proposes the gestalt synapse-based mechanism for critical period ODP, and also predicts a different mechanism for adult ODP based on the sparsity of nascent gestalt synapses at that age. Under our model, early life experience shapes the boundaries  for network function, both for its optimal performance as well as for its pathological state. Thus, reintroducing nascent gestalt synapses as plasticity substrates into adults may improve the network gestalt to facilitate functional recovery.Critical periods are postnatal, restricted time windows of heightened plasticity in cortical neural networks, during which experience refines principal neuron wiring configurations. Here, we propose a model with two distinct types of synapses,  Children learn differently than adults. They learn faster, and the skills that they acquire, stay with them for the rest of their lives. For example, children can achieve native-like proficiency in their second language if it is learned at young ages, but such ability is generally diminished after puberty. The learned second language in adults generally cannot shake off the accent. Thus, acquiring a language as a native depends on the age it is learned and less on the years experiencing it . The leaIn mammalian brains, the formation of cortical neural networks is initially guided by genetic programs, molecular pathfinding, and spontaneous neuronal activity patterns to establish innate functionality. These early networks are immature and rudimental and need a further experience-dependent specification of the excitatory network architecture for instructive functionality . Experiein vivo reference experimental model for studying cortical plasticity. ODP describes a network phenomenon that transcends from cats  . While tTo analyze ODP, visual responses are assessed using various techniques that report different parameters of network activity. These techniques include single-unit recordings , intrinsSingle unit recordings assess the proportion of the recorded cells, responding preferentially to the deprived eye versus the non-deprived eye, and the contralateral bias index (CBI) or ocular dominance index (ODI) is used to quantify ocular dominance shifts by relating the difference in evoked spike numbers. This analysis measures the output, i.e., action potentials from the recorded V1-cells, and reports the proportion of the population preferring one eye over the other. The resulting ocular dominance shift towards the non-deprived eye after MD can be due to either a reduction of the deprived eye responses, or to an increase of the non-deprived eye responses, or to both. In an attempt to quantify changes specific to either eye, responses have been normalized to the firing rate  which isTwo-photon calcium imaging reports changes in calcium indicator fluorescence following action potentials as a proxy for neuronal activity. Similar to single unit recordings, this approach can report whether a neuron prefers one eye over the other, and the CBI is typically calculated. Additionally, the amplitude of the fluorescence change is used as a proxy to compare neuronal responses to either eye’s input in binocular V1 of control and MD animals after normalizing to baseline fluorescence intensity . In contVEPs are complex extracellular field potential recordings induced by visual stimulation. Using one-dimensional current source density analysis to track the signal along the cortical depth, the VEPs induced by visual stimulation are primarily driven through thalamocortical synaptic inputs to layer 4 neurons , but alsIntrinsic signal optical imaging exploits the fact that active neurons consume more oxygen than inactive ones, thereby locally increasing the concentration of deoxyhemoglobin, which absorbs more of the red light that is shone onto the cortical surface for monitoring the visually stimulated activity changes in mostly superficial V1 . Absolutinnate versus gestalt synapses, and silent, unsilenced, versus stabilized state. We will first outline our model for the refinement of excitatory neural networks during critical periods, and then elaborate on how the model is supported by our recent studies and the current body of literature. We will then describe the implications for the cellular mechanisms of ODP and perception. While our discussion is focused on ODP as an experimental model for cortical plasticity and critical periods, we also survey the different expression mechanisms of cortical plasticity at different developmental stages and address results that highlight the general applicability of the discussed principles.In particular, by investigating mouse models using an array of experimental approaches , the fieInnate synapses establish innate network functionality, and gestalt synapses primarily govern experience-dependent refinement of principal neuron connections during critical periods , innate synapses depolarize the postsynaptic membrane upon glutamate binding and mediate fast excitatory synaptic transmission in neuronal networks. During early development, innate synapses thus provide basic functionality by maintaining rudimentary excitatory network activity. The nascent gestalt synapses have an AMPAR-silent state (commonly referred to as silent synapses)  and thusexcitatory synapse maturation during critical periods: repeated correlated neuronal activity of the pre- and postsynaptic neurons induces long-term synaptic potentiation (LTP), and drives AMPARs into silent gestalt synapses, transforming them into unsilenced gestalt synapses which now also contain responsive AMPARs (AMPAR+). These unsilenced gestalt synapses then get either stabilized to become stable gestalt synapses, consolidating a favorable synaptic connection, or get pruned if not timely and sufficiently activated. Thus, at the beginning of the critical period, the excitatory network consists of both rudimentary functional connections with innate synapses and gestalt synapses as potential substrates for experience-dependent network refinement. The coordinated action of unsilencing and stabilization of silent gestalt synapses, and pruning of gestalt synapses in the silent as well as the unsilenced state , underlies excitatory network maturation. This coordinated process sets up the fundamental cortical network architecture (Nascent (silent) gestalt synapses can, therefore, undergo experience-dependent itecture . We thusN-methyl-D-aspartate-type glutamate receptors (NMDARs), but lack AMPARs  in the recipient neurons when the recipient neurons sit at the resting potential. During LTP induction, NMDARs at silent synapses are opened with simultaneous postsynaptic depolarization and presynaptic glutamate release. Ca2+ influx through NMDARs drives Ca2+-dependent signaling cascades that lead to AMPAR incorporation into silent synapses, establishing AMPAR-mediated synaptic transmission  that subsequently responds to presynaptic glutamate release at resting potential    and netwogether) .A critical role of silent synapses in juvenile ODP was revealed by the analysis of knock-out (KO) mice of postsynaptic density protein-93 (PSD-93) and PSD-95 . PSD-93 The developmental increase in the protein expression of PSD-93 in V1 leads that of PSD-95 after eye-opening, and peaks before the critical period, whereas the expression of PSD-95 peaks at the end of the critical period, a result consistent with the opposing yet cooperative interaction of these paralogs in regulating silent synapse maturation . The strThus, under physiological conditions during the critical period, silent gestalt synapse-based refinement alters principal neuron wiring and their progressive maturation ends critical periods.+ synapses were indicated by the analysis of the role of PSD-95 in critical period plasticity. PSD-95 is not required for all stable AMPAR+ synapses. First, the excitatory drive onto PV+ interneurons is unaltered in PSD-95 KO mice  leads to a loss of ∼50% glutamatergic synapses  a result+ interneurons, the differentiation is not possible by the sole presence or absence of PSD-95, but might be rather determined by one of the PSD-95 interaction proteins, such as Celsr3  cortex is overlapping with the critical period of the somatosensory cortex (P11–13), but not with the later critical period in the visual cortex (P21–35) when filopodia numbers are low . While iin vivo two-photon microscopy  gestalt synapses, their partly transient nature is indicated by the observation that the rate of dendritic spine turn-over is high during early cortical development and in PSD-95 deficient neurons, situations when silent synapse numbers are high . Given t2+/calmodulin (CaM) binding protein that regulates the availability of the Ca2+ signal mediator CaM and consequently regulates the activation of the downstream signaling proteins including CaM-dependent phosphatase and CaM-dependent kinase. Tipping the Ca-dependent signaling toward CaM-dependent phosphatase activation by genetically reducing or abolishing the function of neurogranin  during the critical period . We hypo+ synapses at these connections. Similar to the increase in potency by silent synapse maturation in V1, LTP increases the potency in minimal stimulation recordings, consistent with the hypothesis that LTP mechanisms mature silent synapses in vivo  EPSCs remains unchanged throughout the critical period until adulthood  .in vivo patch-clamp recordings of layer 4 spiny stellate neurons in the binocular region, excitatory synaptic inputs are primarily driven by visual stimulation of the contralateral eye in rodents, and the ocular dominance shift resembles that measured with VEPs  or calcium imaging, respectively (Box 1)  or in suith VEPs . The rapce shift . Despitece shift . MD causce shift . This rece shift , enablince shift .ex vivo in visual cortex slices  activation  leads to a delayed increase of V1-responses to the non-deprived eye  a phenom+ synapses instead of silent synapses in adult PSD-95 KO mice? Conversely, in PSD-93 KO mice, silent synapses mature precociously and the critical period for ODP closes earlier, whereas the threshold for LTP in the hippocampus is reported to be elevated  when developmental processes have ceased and plasticity follows different rules. In PSD-93 KO mice, LTP with a classical high-frequency train is similar to that in WT mice. Only with non-classical conditioning stimuli with 5 Hz, a reduction in potentiation in PSD-93 KO mice emerges . HoweverOur survey of the apparent paradox about the mechanisms of critical period plasticity elucidates that synapses may go through stepwise transitions during the critical period, from silent gestalt synapses to unsilenced gestalt synapses that then either get stabilized or depressed and ultimately pruned if not further stabilized . Which oWhile we propose that the expression of ODP is primarily mediated by excitatory gestalt synapses, the opening of the critical period is likely primarily mediated by the maturation of local inhibitory circuits in V1 . The fra+ interneuron-innervated postsynaptic sites of pyramidal neurons  interneurons onto PV+ interneurons increases, while the synaptic strength of SST+ interneurons onto pyramidal neurons decreases. The excitatory synapses within the local cortical network exhibit a similar decrease in short-term depression in different target cell types  in so-called standard cages, which are relatively small, usually translucent cages with woodchip bedding, and water and food mulation .Deprivation of visual experience is generally used to study the role of experience in cortical plasticity. Either animals are raised in the dark from birth until the experimental time point, termed dark rearing, or animals are put into the dark at various developmental stages and for various durations, termed dark exposure. Combining these manipulations with ODP at different ages, one can query how deprivation of visual input can influence experience-dependent plasticity in young and adult animals.After around postnatal day 110, mice raised in standard cages are no longer susceptible to MD, even if the MD was prolonged over 20 days . It is kSome mechanistic insights come from studies on behaviorally interrogated mice with an enriched environment and dark exposure. Both enriched environment and dark exposure, cause a decrease in the inhibitory tone  and bothWe would like to stress that ODP of enriched mice after the critical period, is mediated through non-deprived eye potentiation in V1, a hallmark of adult ODP, already after 4 days of MD . Thus, tConsistent with previous work in cats  and ratsTogether, these results show that both enriched environment and dark exposure  enhance ODP compared to standard cage rodents. It is intriguing how the two seemingly opposite manipulations lead to a phenotypically similar outcome. While mechanisms, such as metaplasticity with experience-dependent modifications in NMDAR subunit composition by dark rearing , and chaThe process of critical period network refinement through the step-wise maturation of excitatory synapses is essential for proper perception in adulthood. For example, juvenile barn owls can learn abnormal associations between auditory cues and locations in visual space if their visual input is displaced by wearing prism goggles, and these abnormal associations are recalled in adulthood if the owls re-experience the displaced sensory inputs by again wearing prism goggles . HoweverIn the rodent visual system, visual perception, as measured by orientation discrimination, is impaired if critical periods close precociously as in PSD-93 KO mice, or if the closure is impaired as in PSD-95 KO mice . In the Binocular matching of orientation tuning and binocular vision require experience-dependent cortical plasticity during critical periods and if this is prevented by dark rearing or genetically impairing critical period refinement, these visual features are otherwise impaired in adulthood . HoweverJudging from the clinical experience in treating neurodevelopmental disorders, merely inducing or enhancing adult plasticity is unlikely sufficient for long-term modification of the network, as a potential pathway to correct network dysfunction caused by developmental deficits. Thus, one provocative idea is to try to rejuvenate networks by engaging critical period plasticity to reorganize/repair connectivity in adulthood. Hijacking the rejuvenation mechanism promises a potential approach that could lead to long-lasting reorganization of the cortical network to correct network dysfunction, such as amblyopia but also other neurodevelopmental disorders that are caused by developmental deficits. Knocking down PSD-95 in adult mice was already shown to restore the fraction of silent synapses to the eye-opening level, and also to reinstate critical period ODP . Togetheinnate synapses that establish rudimentary networks with innate function, and gestalt synapses that govern the experience-dependent refinement process. The maturation of silent gestalt synapses, transitioning via experience-dependent unsilencing and stabilization is a fundamental step in strengthening functional ensembles of the cortical network. The generation, maturation, or pruning of gestalt synapses governs experience-dependent network maturation, and is the essential mechanism for the developmental refinement of cortical principal neuron networks (Using the critical period for ODP in the primary visual cortex as a model system, the field has gained significant insight into understanding the experience-dependent refinement of cortical networks during postnatal development. This process builds the fundamental architecture for achieving optimal functional output after later progressive training . Both exnetworks , 3. Whilnetworks , hippocanetworks , and nucnetworks . Experienetworks . PotentiWhile our new working model raises many questions and challenges, it also provides testable hypotheses and may thus guide further research. First, although we deduced different functional categories of synapses and transitions through different states during experience-dependent network maturation, it remains unknown how the different synapse categories and states are defined at the molecular level. While lack of PSD-95 prevents the transition from unsilenced gestalt synapses to stable gestalt synapses, little is known about the key signaling cascades that control this transition. Our model postulates that unsilenced gestalt synapses are the substrates for LTD and pruning during critical period refinement, which in turn constitutes the expression mechanism of deprived eye depression during MD , 3. BaseOur recent studies provide some initial insights into the molecular mechanisms governing experience-dependent maturation of excitatory synapses, and identified three key players: neurogranin, PSD-95, and PSD-93 . While PNew players are emerging from recent studies, yet, it remains critical to apply the molecular approaches combined with functional analyses to further elucidate how the identified targets regulate excitatory network maturation and perceptual capabilities. Furthermore, cellular and molecular identities involved in glia and astrocyte signaling in regulating postnatal synaptogenesis and synapse elimination warrant further investigation. Finally, the intriguing array of proteins that put a break to critical period plasticity should be investigated in light of synaptic state transitions. Together, the new analyses may answer the key question whether it is possible to preserve or reactivate the generation of silent synapses in the adult brain, to rejuvenate the network gestalt for a critical period-like plasticity to “repair” abnormal configurations of the neuronal networks.All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Continued influx of metagenome-derived proteins with misannotated taxonomy into conventional databases, including RefSeq, threatens to eliminate the value of taxonomy identifiers. To prevent this, urgent efforts should be undertaken by submitters of metagenomic data sets as well as by database managers. Continued influx of metagenome-derived proteins with misannotated taxonomy into conventional databases, including RefSeq, threatens to eliminate the value of taxonomy identifiers. To prevent this, urgent efforts should be undertaken by submitters of metagenomic data sets as well as by database managers. Explosive growth of metagenomic sequences in major databases reflects an impressive progress in development of hardware and software for large-scale shotgun metagenomic sequencing, assembly, and annotation. However, size filtration during microbial sample collection does not provide much protection from eukaryotic cells, such as metazoan sperm or fungal spores, and while bioinformatic tools can correctly assign core eukaryotic or prokaryotic genes to a proper domain of life, they fail to guard against less-conserved sequences systematically misrecognized by computational pipelines. This is especially applicable to poorly studied or rapidly evolving “optional” genes and, most prominently, to transposable elements, often showing deviations in GC-content/k-mer composition and read coverage. With the advent of metagenomics, eukaryotic transposons and understudied gene families are being uncontrollably assigned to prokaryotic genomes and are on track to outpace the well-known problem of eukaryotic genome contamination by associated microorganisms . In the Inclusion of metagenomes in conventional taxonomy-aware databases defies the very purpose of keeping species-specific database records, on which the scientific community has been relying for many years. Most researchers searching GenBank entries tend to trust the description in the nr protein database as definitively excluding environmental (ENV) samples from WGS projects  when theDatabase contamination from metagenomes is an acute problem which is poised to become overwhelming. Unless urgent measures are taken, the value of the taxonomy field in gene annotations will eventually be erased by false positives from misassigned metagenomic bins. Many symbiont WGS projects in fact represent host-associated metagenomes . However5–


Callithrix jacchus. This nonhuman primate model better reflects the human testicular biology than rodents and further gives access to young donors unavailable from humans. Among 5095 identified proteins, 583 were differentially abundant between samples with low and high passage numbers. The alterations indicate a reduced ability of senescent peritubular cells to contract and secrete proteins, as well as disturbances in nuclear factor (NF)-κB signaling and a reduced capacity to handle reactive oxygen species. Since this in vitro model may not exactly mirror all molecular aspects of in vivo aging, we investigated the proteomes and secretomes of testicular peritubular cells from young and old donors. Even though the age-related alterations at the protein level were less pronounced, we found evidence for impaired protein secretion, altered NF-κB signaling, and reduced contractility of these in vivo aged peritubular cells.Age-related changes in the human testis may include morphological alterations, disturbed steroidogenesis, and impaired spermatogenesis. However, the specific impact of cell age remains poorly understood and difficult to assess. Testicular peritubular cells fulfill essential functions, including sperm transport, contributions to the spermatogonial stem cell niche, and paracrine interactions within the testis. To study their role in age-associated decline of testicular functions, we performed comprehensive proteome and secretome analyses of repeatedly passaged peritubular cells from  Aging, in general, is associated with a loss of cellular and tissue integrity and finally leads to irreversibly impaired organ functions . In addiAlthough human testicular peritubular cells (HTPCs) have been the focus of functional studies recently and provide a window into the human testis, these testicular cells are still the least explored cell type of the male gonad . They caModels to study aging-related changes include replicative senescence . SenesceWhen studying human cells, it remains impossible to evaluate the sole impact of age on cells, because of confounding factors, such as medical conditions, previous medications, and lifestyle. Furthermore, although triggering senescence in vitro is an established method to study cellular senescence, the results have to be validated in vivo in order to show their relevance for translational research. To achieve this, a comparison of cells from young and old individuals is mandatory. Obtaining a testicular tissue sample solely for research purposes from young healthy men is unethical and not possible. Therefore, a surrogate nonhuman primate model has previously been established, and the relevance of this model for the human system has been demonstrated . We reasCallithrix jacchus) were from the self-sustaining marmoset monkey colony of the German Primate Center . All animals used for this study were between 2 and 15 years old, i.e., ranging from young adult, sexually mature healthy animals to aged animals . I. I30]. Iproteome . The binAmong the proteins less abundant in hp-MKTPC secretomes were several peroxiredoxins and superoxide dismutases, all involved in the degradation of reactive oxygen species (ROS). This is in line with results from several studies which support the idea that increased ROS is not necessarily the cause, but the result of aging and possibly caused by a reduced abundance of ROS handling enzymes in senescent cells . HoweverStrikingly, in hp-MKTPC secretomes, we found a considerably higher number of proteins decreased rather than increased in abundance compared to lp-MKTPC. This hints to a lower capability of senescent cells to secrete proteins. Furthermore, cadherin-2 (CDH2), a protein important for cell–cell adhesion, and Ras-related protein Rab-1A (RAB1), which was also more abundant in hp-MKTPC proteomes, were the two proteins with the strongest increase in abundance in hp-MKTPC secretomes . These pt-tests nor volcano plot analyses revealed differentially abundant proteins . Furthermore, proteins related to smooth muscle cell contraction were found in the terms “heart development” and in the reactome term “smooth muscle contraction”, both significantly decreased (FDR < 0.05), again indicating a possible loss of contractility. Incidentally, three of the enriched proteins in the downregulated term “regulation of circadian rhythm” were non-POU domain-containing octamer-binding protein (NONO), splicing factor, proline- and glutamine-rich (SFPQ), and paraspeckle component 1 (PSPC1). All three proteins were previously reported to be expressed in Sertoli cells and play a role in androgen receptor signaling . The andC. jacchus model reliably reflects the human system [This study demonstrates that replicative senescence in hp-MKTPCs is associated with a variety of alterations in the proteome and secretome. The detected alterations showed a high degree of similarity to results previously obtained in human TPC, which demonstrates that the nonhuman n system . The detIn addition to studies on TPC senescence induced by repeated cell passaging, the common marmoset model facilitates studies and comparisons of young and older TPCs aged in vivo. Even though the alterations within the proteomes and secretomes of in vivo aged MKTPCs are less pronounced than in in vitro aged TPCs, we again found evidence for an impaired protein secretion, for alterations in splicing, and for a reduced contractility of in vivo aged MKTPCs. These findings demonstrate the involvement of TPCs in testicular aging.However, it has to be considered that, even though proteomics is a powerful research tool, facilitating the quantification of thousands of proteins, proteome alterations alone cannot completely characterize the entire mechanism of a complex process such as cellular aging. Nevertheless, the detected senescence-related proteome alterations and the associated biochemical pathways are particularly valuable and can serve as a basis for future functional and mechanistic experiments dedicated to improving the understanding of cellular aging.


Mammalian retinal ganglion cells (RGCs) in the central nervous system (CNS) often die after optic nerve injury and surviving RGCs fail to regenerate their axons, eventually resulting in irreversible vision loss. Manipulation of a diverse group of genes can significantly boost optic nerve regeneration of mature RGCs by reactivating developmental-like growth programs or suppressing growth inhibitory pathways. By injury of the vision pathway near their brain targets, a few studies have shown that regenerated RGC axons could form functional synapses with targeted neurons but exhibited poor neural conduction or partial functional recovery. Therefore, the functional restoration of eye-to-brain pathways remains a greatly challenging issue. Here, we review recent advances in long-distance optic nerve regeneration and the subsequent reconnecting to central targets. By summarizing our current strategies for promoting functional recovery, we hope to provide potential insights into future exploration in vision reformation after neural injuries. Klf4/9  relay visual related information from the eye to the brain through their axons, which collectively form the optic nerve , the lateral geniculate nucleus (LGN), the superior colliculus (SC), and other visual areas with either longer period after the injury  of RGCs die a few weeks after optic nerve injury , in several studies using combinatory approaches regenerating axons could reach and even cross the optic chiasm. For example, when Pten/Socs3 double knockout was combined with CNTF, 4 weeks  and advanced 3D imaging systems , are emerging to be useful tools for detailed analysis of axon trajectory in the brain.After regenerating axons reach their original brain targets, the next challenge is to achieve new synaptogenesis, remyelination, and the subsequent functional restoration of vision. To date, only a few studies have reported functional reconnection with brain nuclei after optic nerve crush. An early study showed that the combination of Pten deletion with Zymosan and cAMP resulted in long-distance axon regeneration crossing the optic chiasm and into brain structures, including SCN, dLGN, and SC, 10 weeks after the optic nerve injury. Histological evidence demonstrated that regenerating axon terminals appeared to form synapses within the targeted nuclei. Consequently, several innate visual behaviors were partially restored, such as depth perception, optomotor response, and circadian activity patterns  long-distance axon regeneration and correct pathfinding into all major visual targets were observed as early as 3 weeks after the optic nerve injury  with combinatorial approaches, it is possible to induce long-distance axon regeneration to enter the brain; and (2) with proper axon guidance and remyelination, visual function could be restored . The eyeDespite significant progress in RGC regeneration over the past decade, functional repair in the visual pathway still has a long way to go. Based on the above-described studies, an important question is where we should go soon. First, although we have identified many genes that can be manipulated to enhance optic nerve regeneration, our understanding of cellular and molecular mechanisms by which axon regeneration is regulated remain fragmented. For instance, during neuronal maturation what are the key steps and essential regulators that gradually switch off the ability of axon growth? What are the key differences between neurons in the CNS that almost permanently lost their capacity to support axon regeneration, comparing to those in the PNS that can reactivate their intrinsic capacity? Of all the neurons in the same tissue, do they all have the same ability to support axon regeneration? How do other cells in the retina, such as Müller cells, amacrine cells, contribute to the loss of axon regeneration ability of RGCs during maturation and failed regeneration after injuries? Recently developed multiomics approach, such as RNA-, ATAC, and Hi-C sequencing, either at bulk or single-cell level, supported by the advanced bioinformatics analyses, will be very useful tools to address these questions (Tran et al., Second, after long-distance axon regeneration, the next challenge is to guide the regenerating axons to reach their specific targets in the brain, form functional synapses, remyelinate the proper axons, and regain specific visual function. Unfortunately, up to date research in this area remains very limited. Although a few studies have shown long-distance regeneration of optic nerve axons back to all the brain nuclei and some visual function recovery, more studies are needed to confirm these findings. Several previous studies (Luo et al., Third, the current most used animal model of visual injury is the optic nerve crush that is surgically easy and reproducible. However, multiple clinically relevant diseases result in optic nerve injury, such as glaucoma, optic neuritis, optic neuropathy, and optic nerve atrophy. Because different diseases may induce different cellular responses, different animal models mimicking each disease should be utilized before a potential translational application.S-GY, C-ML, and F-QZ designed, wrote, revised, and finalized the manuscript. C-PL edited the manuscript. X-QP designed the figures. Z-QT provided constructive comments. All authors read and approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Sports-related concussions pose a significant public health concern, and preventative measures are needed to help reduce risk in sport. Vision training could be a suitable prevention strategy for sports-related concussion to help improve athletes’ abilities to scan the visual field for oncoming objects or opponents and thus anticipate head impacts. By accurately anticipating impacts, athletes can prepare for impact or attempt to avoid the collision altogether. The purpose of this review is to explore the relationships between anticipation, visual and sensorimotor performance and head accelerations, as well as to examine the efficacy of vision training programmes in reducing concussion risk in sport. Anticipation of head impacts has been shown to help reduce linear and rotational head accelerations, particularly for mild-to-moderate severity head impacts, but less so for severe head impacts. There is conflicting evidence regarding the influences visual and sensorimotor performance and oculomotor behaviour have on concussion risk. However, preliminary research indicates vision training may help reduce concussion rates in collegiate American Football players. Therefore, this promising area of research warrants further investigation, particularly the role of anticipation and visual and sensory performance on reducing concussion risk in non-helmeted contact sports. Sports-related concussions pose a major public health concern internationally.Anticipation and visual performance may influence the severity and frequency of head impacts.There are potential benefits of vision training to aid in reducing concussion risk.Further research is needed to assess the role of anticipation and visual and sensory performance on reducing concussion risk, particularly in non-helmeted contact sports.Concussions are a subset of traumatic brain injuries, which are induced by biomechanical forces, typically resulting in short-term neurological impairments. Following a concussion-inducing head impact, individuals may present with one or more symptoms such as headache, amnesia, irritability, slowed reaction times, sleep/wake disturbances, balance impairment, light sensitivity, tinnitus or loss of consciousness . The comThe incidence of concussion is notably greater in collision and contact sports. Over a 10-year period in New Zealand, 1330 of 20,902 reported concussions from seven team sports were of moderate-to-severe intensity, which predominantly occurred in rugby union (60.3%), followed by soccer (13.8%), rugby league (13.5%), netball (5.6%), hockey (2.6%), touch rugby (2.6%) and softball/baseball (1.7%)  reportedThe incidence of SRC is continuing to increase, with reported statistics likely to underestimate the true incidence of concussion . VariousSchneider et al.  highlighConcussions are caused by either a direct impact to the head, face or neck or an impact to the body that transmits impulsive forces to the head . Concuss−2 have been proposed as such injury thresholds [−2 [Direct contact or inertial forces experienced upon impact can result in excessive linear and/or rotational accelerations of the head . Linear resholds . These hresholds , 33. Howolds [−2 . Furtherolds [−2 . The sevolds [−2 . As suchHelmets and mouthguards are typically used for protection in collision sports, such as American Football and ice hockey. Although this protective equipment helps reduce the risk of superficial head injuries, skull fractures and dental damage, they have not decreased the incidence of concussions , 36. In To further highlight the influence of vision on concussion risk, Clark et al.  observedAnticipation and the ability to quickly process visual cues and elicit appropriate reactions are therefore hypothesised to help reduce the risk of direct head impacts. There are various components of anticipation, including pattern recognition, prioritisation of sensory cues, assignment of situational and event probabilities, gaze behaviour and peripheral vision . DependiNumerous studies have assessed head accelerations and the activation of the neck musculature using a range of head perturbation methodologies including load dropping, quick release of head support and direct head impacts . Load drThe studies that simulated concussion-inducing head impacts through computational modelling produced conflicting results. Jin et al.  simulateThe laboratory-based study conducted by Kuramochi et al.  assessedFor greater sport specificity, head accelerations have also been assessed during rugby union tackling drills  and head−2 [−2 [Head accelerations of actual concussion-inducing head impacts during game play were assessed in youth ice hockey  and high−2 ) were gr−2 [−2 ). As suc−2 [−2 . This inVision is the dominant sensory system and plays an important role in avoiding collisions , 53–55. Hindered peripheral reaction time with helmet use  and poorSchmidt et al.  and HarpBetter performance in the sensorimotor measures relating to eye quickness, visual-motor control and depth perception was associated with less severe head impacts among collegiate American Football players . These fn = 14; skill positions: n = 23), who were also unevenly split between the high- and low-performing groups. There could be additional factors contributing to the severity of head impacts among high school players that were unaccounted for when assessing the influence of visual performance and reaction time alone. Younger players may be more susceptible to sustaining concussions due ongoing development of the nervous and musculoskeletal systems [Within an American Football team, different playing positions require different skillsets and are exposed to different visual stimuli and playing situations. A lack of significant findings among high school players  could be systems , 62. Add systems , this co systems  and be d systems , the NikDifferences in visual and sensorimotor performance scores may have also contributed to the conflicting results, with respect to head impact severity among high school and collegiate players , 58. MyeIn the studies of Schmidt et al.  and HarpAnother aspect of anticipation is gaze behaviour and prioritisation of sensory cues. In order to determine the likelihood of an impact for collision avoidance, individuals need to quickly and accurately scan the visual field by rapidly switching visual focus between various opponents and objects. These brief and simultaneous movements of the eyes between fixations on various targets are called saccadic movements. Kiefer et al.  assessedThe limited research available has provided conflicting results regarding the potential use of sensorimotor training to reduce concussion risk in sport. While anticipation was suggested to reduce rotational head accelerations in moderate intensity impacts in youth ice hockey players , this asVision training has successfully improved visual and sensorimotor performance  and sporVision training using the Nike SPARQ Sensory Station has also been used to effectively improve visual-motor function, but it was not as effective at improving visual sensitivity . An 11-wWhen implementing visual training programmes, it is important to ensure that drills involve higher cognitive processing skills, along with the coupling of visual feedback and appropriate sport-specific motor responses. While the focus of this review has been on vision and anticipation, these factors in isolation cannot reduce concussion risk. Athletes also need to improve their ability to predict event likelihoods, anticipate collisions, make quick and appropriate decisions and subsequently produce an appropriate motor response for avoidance or to brace the head and neck , 55. AdoThis research area is still in its infancy, with few studies investigating concussion risk at game-like intensities , 50 and This review highlights a paucity of research investigating the relationships between visual and sensorimotor performance, anticipation and concussion risk. Studies have largely focused on sports where helmets are required. Although there are few studies available, there appears to be a potential effect of visual performance, oculomotor behaviour and anticipation on the frequency and severity of head impacts in helmeted sports, particularly among highly skilled players. Specifically, better visual-motor control and more effective oculomotor performance allow players to anticipate collisions, which appears to help mitigate the severity and frequency of head impacts. Sports vision training seems to be a promising method to improve visual-motor control and eye quickness that may assist with reducing concussion risk. Visual and sensorimotor performance thus warrants further exploration with regards to its effect on anticipation and mitigating concussion risk, particularly in sports where vision is not compromised by helmet use. The efficacy of visual and sensorimotor training programmes to reduce concussion risk across a wider range of sports and levels of competition also requires further investigation.


Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2, started in the city of Wuhan late in 2019. Within a few months, the disease spread toward all parts of the world and was declared a pandemic on March 11, 2020. The current healthcare dilemma worldwide is how to sustain the capacity for quality services not only for those suffering from COVID-19 but also for non-COVID-19 patients, all while protecting physicians, nurses, and other allied healthcare workers.1 and 16.7%2 in hospitals in New York City and Wuhan, respectively, and up to 44%2 in patients requiring intensive care. Life-threatening arrhythmias (ventricular tachycardia/ventricular fibrillation) can occur in up to 6% of hospitalized patients with COVID-19 infection.3 There have also been several case reports of atrioventricular block in hospitalized patients, which is otherwise rarely described during viral illness.5 Although the residual left ventricular dysfunction and arrhythmic risk are currently unknown, preliminary pathophysiological,6 histological,7 and imaging8 data suggest that severe acute respiratory syndrome coronavirus 2 infection holds the potential to induce durable myocardial changes predisposing to arrhythmias or heart failure.The pandemic poses challenges to electrophysiologists at several levels. Hospitalized patients who are COVID-19-positive may have preexisting arrhythmias, develop new arrhythmias, or be placed at increased arrhythmic risk from therapies for COVID-19. Cardiac arrhythmia incidence in hospitalized patients has been documented in a few published studies, with reported rates of 7.9%10 In parallel, there is a continued responsibility to maintain care of patients who are COVID-19-negative with arrhythmias. These pressures have led to inventive utilization and adaptation of existing telemedicine technologies as alternative options.Electrocardiographic monitoring and inpatient monitoring services may become necessary but face the potential hurdles of limited telemetry wards, contamination of equipment and infection of healthcare personnel, and shortage of personal protective equipment.This document discusses how digital health may facilitate electrophysiology practice for patients with arrhythmia, whether hospitalized for COVID-19 or not. The representation of authors from some of the most severely affected countries, such as China, Spain, Italy, and the United States, is a tribute from our worldwide community to those colleagues who have worked on the front lines of the pandemic.In light of the current pandemic, monitoring strategies should focus on selecting high-risk patients in need of close surveillance and using alternative remote recording devices to preserve personal protective equipment and protect healthcare workers from potential contagious harm.15 The majority of mobile cardiac outpatient telemetry devices can provide continuous arrhythmia monitoring using a single-lead ECG and allow for real-time and offline analysis of long-term ECG data. Telemetry can be extended using patch monitoring.17 Smartphone ECG monitors are wireless and have also been utilized during the current pandemic. Information is limited, however, on how parameters such as QTc measured on a single- (or limited number) lead ECG can reliably substitute for 12-lead ECG information.19 In one study, QT was underestimated by smartphone single-lead ECG.20For inpatient monitoring, telemetry is reasonable when there is concern for clinical deterioration , or in patients with cardiovascular risk factors and/or receiving essential QT-prolonging medications. Telemetry is generally not necessary for persons under investigation without concern for arrhythmias or clinical deterioration and in those not receiving QT-prolonging drug therapy. In situations in which a hospital’s existing telemetry capacity has been exceeded by patient numbers or when conventional telemetry monitoring is not feasible, such as off-site or nontraditional hospital units, mobile devices may be used, for example, mobile cardiac outpatient telemetry as an adjunctive approach to support inpatient care.23 Virtual clinics move far beyond simple telephone contacts by integrating information from photos, video, mobile heart rhythm, and mobile health devices recording ECG, and remote cardiovascular implantable electronic device (CIED) interrogations.24 A variety of platforms have been developed and used specifically to provide telehealth to patients via video teleconferencing26  may allow for a broader reach because of ease and ubiquitous accessibility as a communication strategy for immediate access for urgent matters.There are many barriers to implementation, such as inadequate reimbursement, licensing/regulatory and privacy issues, lack of infrastructure, resistance to change, lack of access/poor internet coverage, restricted financial resources, and limited technical skills . Some telehealth and remote ECG monitoring technologies may be simply unaffordable and/or unavailable, leading to different levels of uptake within communities and across the globe. All stakeholders should collaborate to address these challenges and promote the safe and effective use of digital health during the current pandemic. In recent months, regulations have been eased to permit consults with new patients, issuing prescriptions, and obtaining consents. In that sense, the COVID-19 pandemic may serve as an opportunity to evolve current technologies into indispensable tools for our future cardiological practice.30 Potential COVID-19 therapies, especially hydroxychloroquine and azithromycin, are being investigated in ongoing trials but also have been used off label in many parts of the world. These may exert QT-prolonging effects31  may have synergistic effects on QT prolongation.34 In a retrospective cohort study of 1438 patients with COVID-19 hospitalized in metropolitan New York , cardiac arrest was more frequent in patients who received hydroxychloroquine with azithromycin compared with patients who received neither drug.35 The adjusted hazard ratio for in-hospital mortality for treatment with hydroxychloroquine alone was 1.08, for azithromycin alone was 0.56, and for combined hydroxychloroquine and azithromycin was 1.35. However, none of these hazard ratios were statistically significant. The observational design of this study may limit interpretation of these findings. In the absence of clear efficacy data, treatment options should be individualized taking into account their proarrhythmic potential for torsade de pointes, which may be enhanced by concomitant administration of other QT-prolonging drugs .No specific cure exists for COVID-19.35 If one of these drugs is judged to be critical, monitoring should be initiated. If life-threatening arrhythmias (ventricular tachycardia/ventricular fibrillation) occur, the benefit of antiarrhythmic drugs, notably amiodarone, outweighs the potential harm of hydroxychloroquine or other QT-prolonging drugs targeting COVID-19, and in these cases antiarrhythmic drugs should be prioritized and used as deemed necessary. Most importantly, all modifiable predisposing factors for QTc prolongation  that may enhance arrhythmia susceptibility should be corrected, and the small subset of individuals with an underlying genetic predisposition such as congenital long QT syndrome (in whom QTc-prolonging medications are contraindicated) should be identified. Additionally, caution must be exercised in case of subclinical or manifest myocarditis that may increase the vulnerability to proarrhythmias associated with QT-prolonging drugs.In COVID-19 patients receiving prior antiarrhythmic therapy, there should be a thorough consideration of risk versus benefit before initiating any QT-prolonging COVID-19 therapies, especially considering their unproven value. For instance, although some recent observational studies highlight adverse effects of hydroxychloroquine in treating this infectious disease, its use is likely to persist outside of randomized trials because of its affordability and global availability compared with, for example, remdesivir.50 Low-risk patients treated with QT-prolonging agents may be monitored using MCT (or another available wearable) with twice-a-day transmission of QTc measurements and any urgent alerts. High-risk patients would require more continuous monitoring and follow-up QTc measurements using telemetry preferably . A second QTc assessment via telemetry or other remote devices after 2 doses may be helpful in identifying QTc reactors—patients who have an exaggerated response to QT-prolonging agents. An increase in QTc by ≥60 ms or to QTc ≥500 ms on any follow-up QT assessment is considered significant and should prompt a reassessment of risks versus benefits of continuing the drug.If drugs that exert a QT-prolonging effect are to be initiated in an inpatient setting, a baseline 12-lead ECG should be acquired. Following review of the QTc, patients can be stratified into low-risk group (QTc of <500 ms or <550 ms in the setting of wide baseline QRS) or high-risk group , guiding selection of telemetered versus nonmonitored beds.51 Exceptions to this practice are acknowledged to occur in some regions, as these drugs have been used outside the United States without regulatory warnings. Under these conditions, or when these drugs are maintained after hospital discharge, consumer mobile ECG devices capable of generating QTc measurements may be used. If the QTc increases significantly, physicians can consider a change or discontinuation of medication via the phone or virtual medical services.In the outpatient setting, a recent statement from the US Food & Drug Administration (FDA) “cautions against use of hydroxychloroquine or chloroquine for COVID-19 outside of the hospital setting or a clinical trial due to risk of heart rhythm problems.” 56 These drugs are being tested either alone or in various combinations and are being compared with one another, with differential dosing regimens and/or placebo. These drugs are also being tested for postexposure prophylaxis in high-risk groups.Several double- and multi-arm blind randomized controlled trials are underway worldwide for COVID-19 outpatients utilizing different medications that may prolong the QT interval.Mobile health using smartphone-based portable ECG devices as QTc monitoring tools is an innovative and economical solution to conduct monitoring in outpatient trials. For instance, in one trial evaluating hydroxychloroquine and azithromycin  against a placebo, participants receive remote training to acquire a 6-lead ECG at baseline and then at specified follow-up intervals through the trial period . These ECGs are transmitted to a remote QTc monitoring site, where the QTc is assessed and monitored over the treatment period.10 It has accelerated adoption of telemedicine and all aspects of digital health, regarded as a positive development. Today’s new reality will likely define medicine going forward. Many monitoring and diagnostic testing aspects of both inpatient and outpatient care will be increasingly served by digital medicine tools.The COVID-19 public health emergency has forced changes to traditional norms of health care access and delivery across all continents.57 The use of wearables such as watches, smartphones, and smart beds (with elimination of cables and skin electrodes) for in-hospital telemetry is a novel approach. This type of wireless monitoring may be continued after discharge, permitting prolonged surveillance of rhythm and other physiological parameters.12 Bracelet technologies may transmit multiple parameters  via a smartphone link to centralized hubs. These technologies provide a solution for intensive monitoring extending beyond the hospital environment.The need for contactless monitoring for inpatients triaged to intensive care unit, telemetry, or nonconventional environments, as well as for outpatients needing continued management, has triggered novel implementation of digital health monitoring tools. Some centers have created algorithms based on predictive analytics of electronic medical record data. Centralized monitoring or mobile continuous monitoring has improved patient outcomes, reduced manpower needs, and is being utilized more commonly.58 but less commonly utilized in advanced health systems, have now become the mainstay of ambulatory care across all subspecialties. The initial experience appears to have been positive for both patient and caregiver. Heart rhythm professionals are fortunate to have a choice of wireless technologies to relay monitored information to maintain connection.12 Wearable and smartphone-based devices allow convenient real-time monitoring for arrhythmias on a long-term basis because of the comfort associated with their small size and ease of use while reducing patient and healthcare worker exposure. Remote CIED monitoring has existed for decades.24 It is strongly endorsed by professional societies, but in practice only a fraction of its diagnostic and therapeutic capabilities has been utilized—until now.59 Since the start of the pandemic, utilization of wireless communication with CIEDs has grown exponentially, permanently altering the future of device follow-up. Patient outcomes may be improved with intensive device-based monitoring compared with traditional in-clinic evaluations at regular intervals.60 Recent data indicate that in-person CIED evaluation can be extended safely to at least biennially when daily digital connectivity is maintained.61 Remote monitoring has the potential advantage of detecting and alerting caregivers (and in the future—patients directly) about important parameter changes, enabling earlier patient hospitalization, even during a presymptomatic phase.62Outpatient management has been revolutionized since the start of the pandemic. Social distancing measures and restricted clinic access have driven the rapid adoption of telehealth mechanisms to continue management of non-COVID-19 patients. Virtual visits that have been used for decades to reach isolated communities,63 The ability for CIED remote monitoring data to be streamed to or accessed by multiple providers can facilitate communication and cooperative treatment and should be encouraged. This will require approval by patients, regulators, and manufacturers. Lessons learned from implantable devices can be applied widely in telemedicine. Regulatory bodies have been responsive, for example, approving smartphone-based QT interval measurement and telehealth services across state lines in the United States. The pandemic experience should serve as an impetus to expedite the resolution of persistent challenges, such as validation of digital technologies, infrastructure for data management (and mechanism for relay to patient and caregiver), interoperability with electronic medical record, application of predictive analytics, cybersecurity (and with it the capability for limited forms of remote CIED programming), and reimbursement.66Connectivity permits longitudinal follow-up, with advantages ranging from individual disease management to assessment of penetration of recommended therapies into communities.In summary, the crisis precipitated by the pandemic has catalyzed the adoption of remote patient management across many specialties and for heart rhythm professionals, in particular. This practice is here to stay—it will persist even if other less arrhythmogenic treatment strategies evolve for COVID-19 and after the pandemic has passed. This is an opportunity to embed and grow remote services in everyday medical practice worldwide.None.


Cardiovascular disease (CVD) is the leading cause of death worldwide with mortality rates in women currently exceeding those in men. To date, evidence is widely lacking for unique female determinants of CVD. However, strong associations with psychological stress, obesity or elevated inflammatory biomarkers with adverse cardiovascular outcomes in women have been identified in various studies. Interestingly, amygdalar metabolic activity, a central neural structure involved in emotional stress processing, has proven to be an independent predictor of major adverse cardiovascular events (MACE). Moreover, upregulated amygdalar metabolism was directly linked to myocardial injury in women, but not in men. This newly suggested sex-dependent brain-heart interrelation was further supported by the discovery that bone marrow activity, a surrogate parameter of inflammation, represents a potential bridging link between amygdalar activity and cardiovascular pathology by fueling inflammatory processes that promote atherosclerotic disease. Such malignant cascade of events might account, at least in part, for the excess female mortality seen in women with coronary artery disease and calls for sex-specific research toward pharmacologic or behavioral modulators to improve cardiovascular outcomes, particularly in women. This mini review summarizes recent advances in cardiovascular sex-specific medicine, thereby focusing on the interplay between the limbic system, autonomic regulation and inflammatory biomarkers, which may help to tailor CVD management toward the female cardiovascular phenotype. While the term “sex” is used within the context of biological differences that constitute the female and male characteristics of anatomy and physiology, the term “gender” typically refers to the social and cultural differences between women and men . Indeed,Sex and gender differences play a major role for the diagnosis and management of cardiovascular disease (CVD). Indeed, CVD mortality rates in women in Europe have surpassed those in men . Women dIn this mini review, we aim to highlight neurohumoral sex differences that have been recently linked to CVD. As such, this review focuses on the interplay between the limbic system, autonomic dysregulation and inflammation within the context of CVD.The female propensity toward worse outcomes has prompted a call to reconsider current and traditional risk-stratification methods in cardiovascular medicine . In partA recent study focusing on myocardial function, perfusion, and metabolic amygdalar activity revealed an association between elevated amygdalar activity and impaired myocardial perfusion/function. Notably, these associations were observed in women, but not in men . FurtherFinally, An enhanced sympathetic tone has recurrently been observed in women with CMVD, Takotsubo cardiomyopathy , and ACSActivation of inflammatory processes affects cardiovascular outcomes in both, stable and unstable angina, irrespective of myocardial damage and conventional risk markers of CVD . SimilarIn summary, a sex-specific mechanism linking cardiovascular pathologies with inflammation is so far lacking. Nonetheless, experimental findings suggest a distinct association between sympathetic hyperactivity, upregulation of cytokine cascades, and pathological myocardial remodeling . PotentiCurrently, deleterious sex-specific effects of enhanced psychological stress on cardiovascular health are largely unexplored. However, in an experimental mouse model, A hypothesis with regard to the potential mechanism interconnecting the brain with the heart has recently been suggested by Notwithstanding the substantial progress that has been made in CVD management, current reports still point to a persistent knowledge gap concerning optimized management and risk-stratification in women, particularly with regard to ACS. One of the major challenges to close this gap is to reduce the persistent underrepresentation of females in cardiovascular clinical trials . Furtherevents, interventional studies are required to establish a direct causality. Further, to dissect underlying molecular mechanisms, it is imperative to address pivotal questions including, but not limited to; (1) What are the key components of the immune system that are affected by amygdalar activation? (2) Does amygdalar activation result in impaired cardiac function and/or abnormal cardiac perfusion by triggering sympathetic hyperactivity? (3) Why are women disproportionally affected by emotional stress and what is the role of sex hormones in governing brain-heart interactions? (4) In addition to the prognostic value of enhanced amygdalar metabolic activity, can the “amygdala-related” cardiovascular risk be modulated by therapeutic intervention? Translational molecular imaging has so far played a critical role in elucidating complex interactions of the brain-heart axis. Nonetheless, a multidisciplinary effort will be required to address the abovementioned questions. Further, prospective studies are warranted to translate these intriguing concepts into a genuine advantage for CVD patients.Despite the fundamental knowledge gaps that currently exist in our understanding of the mechanisms underlying brain-heart interactions in CVD patients, there is a growing interest to dissect the pathways involved. As such, initial efforts have been undertaken to understand the role of enhanced baseline inflammation and sympathetic hyperactivity in patients with adverse cardiovascular outcomes. Although an enhanced amygdalar metabolic activity has been linked to adverse cardiovascular All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.All authors have the following to disclose: The University Hospital of Zurich holds a research contract with GE Healthcare. CG has received research grants from the Novartis Foundation and speaker’s fees from Sanofi Genzyme, Switzerland.