External quality assessment (EQA) is a keystone element in the validation and implementation of next generation sequencing (NGS)-based HIV drug resistance testing (DRT). Software validation and evaluation is a critical element in NGS EQA programs. While the development, sharing, and adoption of wet lab protocols is coupled with the increasing access to NGS technology worldwide, rendering it easy to produce NGS data for HIV-DRT, bioinformatic data analysis remains a bottleneck for most of the diagnostic laboratories. Several computational tools have been made available, via free or commercial sources, to automate the conversion of raw NGS data into an actionable clinical report. Although different software platforms yield equivalent results when identical raw NGS datasets are analyzed for variations at higher abundance, discrepancies arise when variations at lower frequencies are considered. This implies that validation and performance assessment of the bioinformatics tools applied in NGS HIV-DRT is critical, and the origins of the observed discrepancies should be determined. Well-characterized reference NGS datasets with ground truth on the genotype composition at all examined loci and the exact frequencies of HIV variations they may harbor, so-called dry panels, would be essential in such cases. The strategic design and construction of such panels are challenging but imperative tasks in support of EQA programs for NGS-based HIV-DRT and the validation of relevant bioinformatics tools. Here, we present criteria that can guide the design of such dry panels, which were discussed in the Second International Winnipeg Symposium themed for EQA strategies for NGS HIVDR assays. Drug resistance testing (DRT) methods for HIV-1 are continually evolving as exemplified by NGS technology, which is gradually replacing Sanger chemistry in clinical diagnostics . NGS hasReference materials or proficiency test (PT) panels have long been used in the validation of experimental procedures and EQA applications for laboratories performing Sanger-based HIV-DRT ,8,9. WhiSoftware pipelines that support NGS HIVDR assays are required to perform a series of data analytical steps to covert raw NGS data into an HIV drug resistance report. While some variations exist, these pipelines share many essential procedures, including filtering of short and poor quality reads, reference alignment, variant calling, drug resistance mutation (DRM) identification, query against selected clinically validated algorithm(s), and a final data reporting step ,11,12. MThe primary applications of a dry panel in genotypic assays include: (1) facilitating the development, refinement, and validation of effective data processing software or bioinformatics tools; (2) enabling technical training and troubleshooting on issues that arise from non-lab procedures; and lastly but most importantly; (3) allowing EQA assessment of the lab competence in relevant data management while involving no real sample processing. Therefore, well-designed dry panels for a genotypic assay should include reference sequences representing raw sequencing outputs containing all major variations, possible artificial biases, and uncommon sequencing errors one may encounter while processing genuine NGS HIV-DRT data.The ground truth or reference values for the subjects of interest  should be pre-determined, against which downstream comparative analyses could be conducted. The ground truth represents the reference values against which the specificity, sensitivity, and additional accuracy and precision quantitative measures could be determined. These can include a reference resistance genotype, a genetic sequence, the presence/absence of specific mutations, or additional information regarding the quality grade of the data.In addition to standard PT specimen panels, capacity building and EQA programs for Sanger-based HIV-DRT have previously benefited from the use of data dry panels ,21,22,23Similar to SS, to-be-developed dry panels for NGS DRT are expected to satisfy all alike needs with additional capacity in the quantitative assessment of NGS output for HIV DRM detection. In addition, NGS dry panels should also represent NGS data variability, with a broad scope of potential errors and artifacts that may arise from the manipulation of samples in NGS experimental protocols. The main goals of an HIV-DRT NGS dry panel are to: 1) test the ability of a bioinformatic tool/pipeline to reliably predict a resistance profile; 2) accurately detect HIV DRMs in both qualitative and quantitative manners; and 3) comply with a standard of quality while being representative of the different NGS technologies and the application context, including error profiles of sequencing platforms, HIV diversity and variability, and experimental design.For this, several measures of agreement between ground truth and the results derived from varied software can be obtained and automatically implemented to score the validity of results when NGS data are analyzed. At the consensus (Sanger-like sequence) level, a single sequence representing the whole NGS-based viral population, the number of discrepancies or nucleotide mismatches between the ground truth sequence, and the obtained sequence should ideally be 0 in terms of similarity across the genome region examined. In addition, a measure of similarity can be measured for every pair of ground truth result data to detect those sequence datasets where the analysis has failed to provide an equal representation of the consensus sequence for the viral population. These measures include phylogenetic distances and tree building that include within-codon mixtures or the calculation of the proportion of differences a. On theThe First Winnipeg Consensus proposed prototypic guidelines specific to NGS data analysis for HIV-DRT, which may serve as a scaffold when designing dry panels for such assays . It specThe sensitivity and specificity assessment of NGS HIV-DRT pose different challenges, compared to SS HIV-DRT, because of the quantitative nature and higher sensitivity of such assays . NGS HIVCurrently, Illumina and Ion Torrent are the dominant NGS technologies used for HIV-DRT ,27. EachIn addition, several experimental strategies exist for NGS sequencing of the HIV genome. For instance, genome sequencing- or amplicon sequencing-based experimental designs may show different features in the data that result in different biases in terms of sequence duplication, recombination, or template sampling. It is also common to aim for different depths of coverage or use diverse sequencing lengths in order to balance laboratory costs. All such factors should be taken into consideration while constructing the perspective dry panels for NGS HIV-DRT. Unique Molecular Identifiers have also been proposed as a way to overcome the bias introduced at the DNA amplification steps and correct for sequencing error, provided that specific data analysis steps are used ,29. ThusThe data format of dry panel files needs to be readily usable by all different software platforms. FASTQ and SAM/BAM are used by most common sequencing platforms and are suitable for data exchange. On the other hand, to be able to exchange and evaluate results in a timely and reproducible manner, the amino acid variant format (AAVF) was defined by the First Winnipeg Consensus . This foReal data are the primary real-world source of data for HIV-DRT bioinformatic tools. Importantly, real data harbors actual errors and artifacts derived from experimental protocols. Real data can be obtained from HIV RNA extracted from patient samples, HIV culture supernatants, or HIV DNA using commercially available HIV plasmids, commonly used in most diagnostic labs as positive controls. Each of these genetic material sources shows specific features in terms of quality control. For instance, plasmid-derived NGS data do not show errors linked to the reverse transcription step needed to process RNA samples.The use of plasmids or RNA from culture genetic material provides a way to create artificial viral mixtures with controlled MRV abundance of interests. Still, the quantification of such mixtures shows intrinsic error and variability. Thus, its link to the readouts from different data analysis tools on the same NGS dataset and its usability as ground truth can’t be derived solely from those measured concentrations.Similarly, one of the main disadvantages of using real datasets for dry panel design is that the ground truth of the exact frequencies of the DRMs they harbor cannot be reliably determined. As an approximation to ground truth, the majority vote consensus of results obtained from several well-established tools could be used to establish the ground truth which could then be used to measure the accuracy of additional tools as they become available . This isOnce a methodology has been established to define ground truth for real data by using statistical agreement, datasets obtained from clinical specimens, viral culture, or plasmid samples can be obtained and analyzed through generic or HIV-DRT specific repositories such as NCBI/SRA and EMBL/ENA or HIVdb-NGS , respectAside from real-world data, the generation of synthetic data has been widely used to test software in all biomedical fields using NGS technologies ,33,34. AA forged dry panel can be described as a carefully crafted combination of real data sequence reads in order to create real datasets with a known ground truth supporting them. The main idea behind a forged dry panel is the careful annotation of NGS sequence data at the read level, by linking each read to the presence/absence of mutations, technology, experimental design, quality score, HIV-1 genome region, and other artifacts that reads harbor. By adding up all these read-level annotations, a composite read data library can be built with thousands or millions of reads that can be combined into forged sample datasets by selecting the reads with the properties expected to be tested in the dry panel. In this way, the real error profile is kept and the specific features to be tested can be combined in a controlled manner.To date, most of the available software tools for NGS-based HIV-DRT have been validated through internally generated datasets. Few studies have reported validation using different data analysis methods and often comparing different sequencing platforms ,36. WhilA comprehensive dry panel should be able to test all of the required quality criteria in a minimal dataset. The First Winnipeg Consensus outlined the essential data analysis steps for NGS HIV-DRT . AccordiFor sequence quality control, short or low-quality sequence reads can be included that harbor a specific signal mutation that should not pass acceptable quality filters. Similarly, highly contaminated or cross-contaminated samples can be included in the dry panel dataset to ascertain if the analysis software can correctly detect and/or describe sample contamination and its source.pol gene sequence, albeit this may not be a requirement for some analysis strategies. HXB2 is suggested as an aligner reference based on considerations including: (1) HIV-1 pol gene is highly conservative among all HIV subtypes, for which the choice of reference has minimal impact on subsequent alignment; (2) HXB2 is a common coordinate system for HIV-1 DRM calling and reporting; (3) the use of a “unified” aligner reference facilitates inter-lab or inter-pipeline comparisons during EQA. Insertions and deletions with respect to a reference are especially challenging to detect and manage, which can benefit from codon-aware alignment strategies and improved alignment quality control [The sequence alignment strategy is a central point in NGS-based HIV-DRT and also needs to be considered for dry panel design. Many alignment algorithms and derived software tools exist that can be used for HIV-1-DRT. The performance of these alignment tools may vary depending on the error profiles of varied NGS platforms and on the genetic diversity of the examined genomic regions . Aside f control ,42. BothFor the variant calling quality control step, the Winnipeg Consensus recommended using codon-level variant calls and reporting, advising against the use of consensus sequence to represent NGS-based drug resistance data. This is because mixed bases present at two or more loci within a codon may result in artifactual or assumptive mutations if only data at consensus level are interpreted. Inclusion of such within-codon mixes is therefore advised to check whether the analysis software is treating variants at the codon-level or nucleotide-level. Additional controls for variant calling include minimum count number of specific mutations and minimum coverage to call variations at a specified threshold since sensitivity is dependent on the depth of coverage.In order to perform an accuracy/precision assessment of the results, the most important measure is the agreement between the obtained drug resistance profile and pre-determined ground truth, which may serve as the ultimate standard. To assess accuracy, specifically for MRV, the presence or absence of amino acid mutations above these different reporting thresholds can be detected and true/false positive/negative measures calculated as the matching or mismatching with the ground truth that is linked to the sample data. This will allow accuracy measures calculation and validation of specific software when reporting drug resistant variants at different thresholds. In addition, a linear correlation between the obtained frequencies of amino acid mutations and the ground truth mutations can also be calculated to obtain generic linear correlation measures and assess the precision of the tool being evaluated.Finally, HIVDR reporting of the obtained results in a standardized format is critical for the ability to exchange and validate results obtained from a dry panel or real data. Systematic EQA programs will benefit from the standardized format. The First Winnipeg Consensus recommended AAVF format specification as an additional report that would be useful for automatic result validation. This format includes codon coverage, mutation frequencies, reference, and the analysis features that are needed for traceable result validation. Therefore, reference AAVF outcomes from the prospective dry panels should be provided as part of the ground truth for pipeline validation or EQA assessment purposes, along with automatic parsing and comparison tools.EQA capacity building programs, as well as software development for NGS-based HIV-DRT, will benefit from strategically designed and well-characterized dry panels that remain to be established. Many challenging but essential requirements need to be taken into account while constructing such dry panels. With the increasing adoption of NGS HIV-DRT worldwide, more research and development efforts are desired for the construction, validation and appropriate application of these panels, especially to serve the needs for effective EQA for such assays.


Rhizobia improve legume N nutrition, and modulate other aspects of host nutrition and development. Symbiont impact on host resource allocation and root distribution, important for soil resource acquisition, is discussed. 2 in root nodules to supplement their nitrogen (N) requirements. Many studies have shown how symbioses affect the shoot, but far less is understood about how they modify root development and root system architecture (RSA). RSA is the distribution of roots in space and over time. RSA reflects host resource allocation into below-ground organs and patterns of host resource foraging underpinning its resource acquisition capacity. Recent studies have revealed a more comprehensive relationship between hosts and symbionts: the latter can affect host resource acquisition for phosphate and iron, and the symbiont’s production of plant growth regulators can enhance host resource flux and abundance. We review the current understanding of the effects of rhizobia–legume symbioses on legume root systems. We focus on resource acquisition and allocation within the host to conceptualize the effect of symbioses on RSA, and highlight opportunities for new directions of research.Legumes form symbioses with rhizobia to fix N The term ‘root system’ typically refers to the entire root network of a plant, and hence its root system architecture (RSA) is the distribution of this network in space which determines the plant’s capacity to absorb soil resources . Hence, in situ in the pedosphere, can inform on the plant’s resource capture and use strategies -rich compounds such as sugars and amino acids, are likely to have a bigger impact on RSA. Therefore, studying how these interactions modify RSA, as well as nutrient acquisition, shoot and root development, plant biomass, and C fluxes will result in a more comprehensive understanding of the different mechanisms and regulatory pathways through which RSA is regulated. In this review, we will focus on the legume–rhizobia symbiosis as a model for how microorganisms modify RSA.2 inside modified roots called root nodules . NIN is a transcription factor that increases the expression of both nuclear factor-Y (NF-Y) subunit genes NF-YA1 and NF-YB1, and ASYMMETRIC LEAVES LIKE 18/LATERAL ORGAN BOUNDARIES DOMAIN 16 (ASL18/LBD16). NF-Y and ASL18 proteins interact with each other to relay the rhizobia-mediated signal which ultimately initiates development of the nodule primordia through activation of cell division in the cortex layer  . When thArachis hypogaea L.). Endodermis and pericycle cells also form part of the developing nodule; however, these are not infected by rhizobia , for example in peanut  and PLETHORA are up-regulated at the initiation site of both LRs and nodules. Furthermore, higher expression of auxin response factors and auxin biosynthesis genes such as YUCCA are also common to both processes  signalling, because enhanced sucrose transport to sink organs via phloem augments the amount of auxin transported by this route . A majorActive symbioses provide a continuous N supply, decreasing host requirements for N foraging. Consequently, if N is no longer the most limiting resource, host resource partitioning and acquisition are predicted to be correspondingly altered to prioritize the assimilation of other, now more limiting, soil resources such as P. To maximize the host’s return on its overall below-ground investment, it would need to modify its foraging strategy, and hence root development, to efficiently use root-allocated resources to absorb these more limiting resources , treatment with several rhizobial strains failed to increase root length  and Arabidopsis, nitrate and ammonium activate N utilization and signalling pathways, for example by expression of nitrate-responsive genes  will rapidly limit growth. Consequently, root foraging for limiting resources is predicted to alter root growth patterns and timing (RSA) by modifying resource partitioning, including by changing plant growth regulator homeostasis ; in some cases, >90% of the strains that nodulate single host species produce it Vigna munVigna radiata) varieties with symbionts that produce high IAA levels in vitro increases root length and mass  by rhizobia modifies root auxin signalling which also results in changes to RSA. In Arabidopsis, colonization by rhizobia leads to inhibition of PR growth and a 2-fold enhancement in the number of LRs, primarily through altering auxin signalling  deaminase which metabolizes the ethylene precursor ACC  inhibit nodulation by detecting CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptides, while the likely receptor of C-TERMINALLY ENCODED PEPTIDE (CEP) peptides, the leucine-rich repeat receptor-like kinase (LRR-RLK) COMPACT ROOT ARCHITECTURE2 (CRA2), stimulates nodulation. Furthermore, in L. japonicus, HAR1 modulates nodulation by inhibiting shoot–root mobilization of miR2111 that represses the nodulation suppressor TOO MUCH LOVE (TML), and by enhancing CK synthesis through activation of ISOPENTENYL TRANSFERASE 3 (IPT3) and translocation to roots to suppress further nodulation events through their receptor LOTUS HISTIDINE KINASE1 (LHK1)  is shown in In legumes, two shoot-expressed receptors independently and antagonistically regulate nodulation systemically by perceiving mobile signalling peptides produced in the root contingent on soil N availability and infection status , and LIKE SUNN SUPERNODULATOR (lss), also have altered biomass allocation, LR length, and density, similar to what sunn mutants. This is observed independently of nodulation, which exacerbates these differences due to increased resource competition between roots and nodules. Finally, in L. japonicus, the ROOT DETERMINED NODULATION 1 (RDN1) orthologue PLENTY and HAR1 regulate PR length, LR number, and development under both nodulated and uninoculated conditions . A further example is NIN, whose paralogues are M. truncatula, this transport is essential to balance C allocation between shoot and roots in response to variable N availability: balancing C allocation for shoot and roots maintains growth homeostasis and depends on the AON gene SUNN  X-ray tomography or MRI; and (ii) rhizoboxes. The former systems scan pots up to 80×15 cm and reconstruct a 3D image of the roots, both thick and fine, but are very costly . HoweverThe use of these systems to study RSA in a variety of conditions in many symbioses will provide a better understanding of the role of rhizobia in altering legume RSA. For example, systems of larger dimensions allow for longer periods of unrestricted root growth where more evident changes in RSA could be observed. This would also include those that appear only late in the life cycle, specifically after flowering, when nodulation decreases leaf senescence and enhances C assimilation and allocation to roots . For example, high auxin-producing strains could increase root C allocation, as well as length and area of the root system compared with strains that produce low IAA levels  upon symbiosis depends on both partners as well as environmental conditions. Rhizobial symbioses can enhance not only host N but also macro- and micronutrient availability, specifically P and Fe, and some have the ability to additionally sculpt host growth and resource flux and partitioning by producing plant growth regulators such as auxins. Therefore, effective symbioses result in extensive and complex changes that permit the host to modify resource allocation patterns to roots such that its RSA optimizes acquisition of limiting soil resources. Hence, interactions with other microorganisms, such as mycorrhiza and free-living soil bacteria, might also impact RSA depending on which mechanisms and regulatory pathways are stimulated and to what degree. Therefore, RSA embodies host resource partitioning decision making, as well as rhizobia-modified legume nutrition, C flux, and hormonal signalling. This highlights the great utility of time-series experimental studies of RSA in nodulated and non-nodulated hosts to inform on resource partitioning mechanisms, required to develop more resilient and resource-efficient legume and non-legume crops.Legumes are important crops due to their ability to establish symbioses with rhizobia that allow them to fix N


Burn injury in the craniofacial region causes significant health and psychosocial consequences and presents unique reconstructive challenges. Healing of severely burned skin and underlying soft tissue is a dynamic process involving many pathophysiological factors, often leading to devastating outcomes such as the formation of hypertrophic scars and debilitating contractures. There are limited treatment options currently used for post-burn scar mitigation but recent advances in our knowledge of the cellular and molecular wound and scar pathophysiology have allowed for development of new treatment concepts. Clinical effectiveness of these experimental therapies is currently being evaluated. In this review, we discuss current topical therapies for craniofacial burn injuries and emerging new therapeutic concepts that are highly translational. Burn injuries represent one of the leading causes of accidental death worldwide. In the United States alone, burn incidents that demand medical treatment exceed more than 400,000 cases each year, ∼40,000 of which require hospitalization and intensive post-burn care . Over 50Despite modern advances in surgical techniques and biomedical technologies, management of facial burns remains challenging and post-burn scar formation may be inevitable. The approach to treating a burn wound begins with accurately diagnosing the depth and size of the burn, which is of critical importance for deciding the timing and approach to management. Superficial (first-degree) burns heal without the need for surgery and typically do not lead to adverse scar formation or hyperpigmentation as the entire dermis is preserved. Superficial partial thickness (second-degree) burns typically heal spontaneously within days to weeks and may result in scarring. Deep partial-thickness burns and full thickness (third-degree) burns usually require excision with reconstruction (often skin grafting) and are more prone to developing HTS. It is generally accepted that any burn that is not expected to heal on its own within 3 weeks should undergo excision and grafting as early as is feasible. This is due to the increasing risk of HTS that doubles from 20 to 40% between 2 and 3 weeks, as demonstrated by Although exuberant fibro-proliferation in the burn area starts as part of the normal wound healing, variations in cellular responses can lead to excessive scar-producing processes . Recent Burn injuries can vary widely in severity, ranging from local tissue damage to a complex systemic response which can quickly become life threatening. The complete local and systemic pathophysiology of burn injury has been reviewed in detail elsewhere and is beyond the scope of this review . Here weAt a molecular and cellular level, burn wounds are characterized by a surge in reactive oxygen species (ROS) production leading to oxidative stress, inflammation, and coagulative tissue necrosis . Hypoxia1.Zone of coagulation/necrosis: this zone is characterized by complete vascular destruction and irreversible tissue loss.2.Zone of stasis: this zone sustains a moderate degree of damage with some vascular damage leading to compromised tissue perfusion. This zone shows variable outcomes and may eventually recover or progress to necrosis.3.Zone of hyperemia: this zone is characterized by vasodilation resulting in increased blood flow and hyperemia and will recover without any fibrosis or scarring.In addition to direct tissue damage, burn injuries also result in microvascular fluid egress, which causes a sharp increase in localized edema that occurs within the first hour following injury . ActivatBeyond the acute injury phase, burns are characterized by chronic activation of transforming growth factor-beta (TGF-β) and MCP-1, resulting in inflammation, fibroblast proliferation, collagen synthesis and deposition, and remodeling of the new extracellular matrix (ECM) . PersistThe craniofacial region contains a rich anatomy with many unique and specialized structures that deserve special consideration in the context of burn injury. The robust vascular supply of the head and neck allows for many areas to recover quite well from superficial partial thickness burns. However, deeper injuries to functionally and esthetically important areas can result in significant functional and cosmetic sequelae for patients. Several key anatomical areas are discussed below, and are illustrated in Burn injuries of the eyelids can cause lid malposition resulting in cicatricial ectropion or entropion, potentially leading to long-term problems with vision including corneal ulceration and even blindness . All thrThe auricle deserves special consideration given its cartilaginous structure which lies directly underneath the skin. The cartilage is therefore at risk of chondritis following full thickness burn injury . TopicalNasal burns can cause facial disfigurement that can negatively impact patients’ psychosocial health . These iBurn scarring of the perioral region can result in purse-stringing of the oral aperture, microstomia, drooling, shortening of the columella, and cicatricial ectropion of both the upper and lower lips . These cScarring in the neck region can result in contractures that limit neck mobility, mastication, phonation, or breathing, and may cause neck pain and esthetic concerns . TreatmeIn contrast to the scarring phenotype seen on the exterior head and neck, the oral cavity is characterized by a remarkable ability to heal with minimal scarring . With thGiven the remarkable advances in acute burn resuscitation and care that have evolved over the past century, burn injuries are becoming an increasingly survivable injury. As a result, preventing, minimizing or correcting the long-term sequelae of burn scars is becoming increasingly important for improving the quality of life of patients. In the following sections we will review the history and advancement of burn care, discuss current therapies for craniofacial burn treatment and discuss new and emerging therapies to reduce post-burn scarring.Unfortunately, burn injuries are also as old as our own history. The ability to create and manipulate fire is one of the quintessential characteristics of mankind dating back millennia. There is a rich history of our understanding of burns and approach to burn care, found in texts dating back to ancient Egypt . In paraAmbroise Paré was likely the first to describe early burn wound excision in the mid-16th century . Later, Following the Cocoanut Grove nightclub fire in Boston, MA in 1942, which killed and injured hundreds of patients, doctors noted that larger burns would result in hypovolemic shock without fluid resuscitation . Prior tFluid resuscitation, early excision and grafting, and infection control have led to significant improvements in burn morbidity and mortality. In the following sections we explore in detail modern methods of craniofacial burn wound care, as well as new and emerging therapies targeting post-burn scar mitigation.Most craniofacial burns spontaneously heal and do not require surgery given the head and neck are well vascularized. Non-operative therapies for post-burn scarring are primarily aimed at reducing the risk of wound site infection and facilitating the debridement of necrotic tissue. The TIME  concept represents a systematic approach for assessing and treating wounds, and provides a useful reference for categorizing topical burn therapies . The curTo prevent infection, silver preparations such as silver sulfadiazine (SSD) and silver-containing dressings are commonly used for the treatment of second and third-degree burns. However, these agents are discouraged in the face due to their adverse effects on mucosal membranes of the eye, nose, and mouth. Topical ointments such as bacitracin, polymyxin, and mupirocin are used instead . Silver Early debridement allowing for healthy tissue regrowth is the cornerstone of burn wound care and is vital to the overall outcome of burn patients. The practice of excising burn eschar in the facial area, however, remains controversial, given its robust blood supply which is favorable to spontaneous healing within an acceptable period. For debridement, surgical excision and/or proteolytic enzymes that digest necrotic tissues can be used. Surgical excision may be performed sharply using a Weck, Goulian, or Watson blade. Alternatively, mechanical debridement may also be performed using hydro-powered devices such as the Versajet , or ultrasonic debridement devices. Bromelain-based agents are most used for enzymatic debridement, however, this method can slow healing time and cause significant pain. For these reasons, use of enzymatic agents has been generally avoided for facial burns thus far.Growth factors and cytokines play a key role in wound healing, including the promotion of proliferation and migration of various cell types, recruitment of circulating inflammatory and progenitor cells, and stimulation of angiogenesis and ECM production . TopicalBurn wound dressings are made from a variety of materials including silicone, chitin, alginate, hydro-polymers, and polyurethane foam. Dressings containing therapeutic agents such as aforementioned silver compounds are also used. Use of hyaluronic acid-based wound dressings has been reported to be safe and effective for partial-thickness facial burns. Silicone sheet dressings have been shown to soften post-burn scars, prevent contracture and increase skin and joint mobility. These effects are attributed to greater tissue hydration, which results in improved scar texture and color .® Life Science Corporation, Plainsboro, NJ, United States). Originally developed by Harvard and MIT scientists, Integra® is an artificial acellular bilayer composed of a bovine collagen type I and chondroitin-6-sulfate dermis, with a semipermeable silicone membrane “epidermis.” The silicone membrane is left in place for at least 2 weeks, allowing for sufficient neovascularization to take place to allow for skin grafting over the dermal substitute  benefit from providing natural dermal porosities to support tissue regeneration and neovascularization while providing wound protection .®  is a human cadaveric allograft which is chemically decellularized using mild non-denaturing detergents, while the collagen matrix is preserved. Bioengineered allograft materials can also contain cellular components, such as Apligraf® , a cellular bilayer substitute containing bovine collagen type I dermis, as well as allogenic neonatal keratinocyes and fibroblasts  have shown promising results in the treatment of chronic wounds in clinical trials  allografts such as EpiBurn or EpiFix, can be used to protect the wound while promoting vascular angiogenesis and healing . SimilarFinally, xenografts offer an alternative method for obtaining wound coverage with the added benefit of improved cost and availability, as compared to allograft materials. Compared to human ADM, xenograft ADM has demonstrated strong protein homology and equal biocompatibility . ExampleWhile various physical therapies and operative procedures can facilitate burn wound healing and minimize post-burn scars, use of these treatment modalities is not always suitable for craniofacial burns. Topically applied pharmacological agents are also effective treatments, especially during the acute phase, but choices are limited. Antimicrobial and enzymatic agents have been used primarily to prevent infection and promote debridement of necrotic tissues. Several vitamin preparations and plant-based remedies are also available. However, many topical therapies lack concrete scientific evidence and results have been variable. As our knowledge of the mechanistic basis of wound healing and scar development improves, approaches to develop molecularly targeted therapies have shown promise . These tTGF-β expression is involved in almost all stages of the wound healing process, including inflammation, angiogenesis, re-epithelialization, ECM synthesis, and wound remodeling. Many studies have established the pivotal role of this growth factor in myofibroblast differentiation and subsequent scar formation across a range of fibrotic diseases . StudiesDespite strong pre-clinical outcomes, current TGF-β clinical trials have had disappointing results. Juvista , a recently-developed recombinant TGF- β3 product, had shown promise in early phase efficacy trials but failed to meet primary endpoints in a Phase III trial . JuvidexNeutrophils and macrophages, two of the major cell types during the inflammatory phase of burn injury, secrete cytokines such as interleukins (IL) and tumor necrosis factor β (TNF-β) . IL-10 hMechanical stress is an important component of wound healing and plays a pivotal role in facilitating pro-fibrotic events via cellular mechanisms that stimulate inflammatory pathways . Over-acDespite success on surgical incisions, polymer mechanomodulatory devices are difficult to use on large size excisional wounds, burn injuries, and wounds that formed in contoured body areas such as the facial area. Alternatively, non-invasive therapeutics that pharmacologically target key mechanotransduction pathways , is a key upstream mediator of the Integrin mechanotransduction pathway and an important inducer of cell adhesion, proliferation, migration, and angiogenesis . FAK is In current literature, small molecule-mediated inhibition of the kinase activity of FAK has been successfully used to prevent mechanically-induced skin HTS formation . FAK inhMedicated self-adhesive patches that release therapeutic molecules upon dermal contact may not be suitable for large size burn wounds, and other topical formulations in the form of topical cream, lotion, or ointment are easily subject to over- or under-dosing if application amount per treatment is not accurately measured. The latter is also problematic especially for compounds with potential adverse effects at the systemic level . TherefoCell-based therapies have emerged as an important component of regenerative medicine. Stem cells of various sources and cultured dermal cell devices such as epithelial sheets have shown merit when used as an alternative or in conjunction with standard skin grafting techniques for therapeutic application in severe burn injuries. The technology, however, are highly regulated by authorities globally and consistent concerns have been raised as to the biosafety and clinical efficacy of cell-based therapies .Despite scientific concerns, many autologous and allogeneic cell products were developed over the past decades using cells of skin and non-skin origins in burn wound management . CultureTraditional evaluation of post-burn scarring is primarily based on subjective measurements such as scar assessment scales. However, comparative success of new experimental therapies should also depend on objective assessments that use a variety of standardized techniques and devices. Detailed discussion of these tools is beyond the scope of this review and can be found elsewhere . RegardlBurn scarring and fibrosis are responsible for a significant burden on patients and healthcare systems across the globe. The sequelae of these injuries can be especially challenging to treat in the craniofacial area given its unique functions and its significant relevance for psychosocial health. Although the craniofacial area benefits from robust vascularity and healing, careful consideration must be given toward injuries in particularly sensitive areas, such as the eyelids, nose, ears, mouth, and neck, as these require special reconstructive considerations. As our understanding of wound healing and fibrosis evolves, new minimally invasive therapies may offer exciting alternatives to traditional tangential excision and skin grafting, potentially leading to improved outcomes for patients and significant cost savings. Research is ongoing to identify and translate promising new therapies into the clinical arena.SK, JB, CN, KC, DH, CS, and GG wrote the manuscript. All authors contributed to the article and approved the submitted version.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.


Chronic excessive alcohol use is a well-recognized risk factor for pancreatic dysfunction and pancreatitis development. Evidence from in vivo and in vitro studies indicates that the detrimental effects of alcohol on the pancreas are from the direct toxic effects of metabolites and byproducts of ethanol metabolism such as reactive oxygen species. Pancreatic dysfunction and pancreatitis development are now increasingly thought to be multifactorial conditions, where alcohol, genetics, lifestyle, and infectious agents may determine the initiation and course of the disease. In this review, we first highlight the role of nonoxidative ethanol metabolism in the generation and accumulation of fatty acid ethyl esters (FAEEs) that cause multi-organellar dysfunction in the pancreas which ultimately leads to pancreatitis development. Further, we discuss how alcohol-mediated altered autophagy leads to the development of pancreatitis. We also provide insights into how alcohol interactions with other co-morbidities such as smoking or viral infections may negatively affect exocrine and endocrine pancreatic function. Finally, we present potential strategies to ameliorate organellar dysfunction which could attenuate pancreatic dysfunction and pancreatitis severity. Based on a 2018 report from the World Health Organization (WHO), alcohol abuse accounted for ~3 million deaths  worldwide in 2016  and endoPancreatic islet cells are responsible for the secretion of metabolic hormones insulin and glucagon. Insulin is a critical hormone that regulates carbohydrate and lipid homeostasis. Several clinical and preclinical studies have revealed that alcohol consumption impairs basal and glucose-stimulated insulin secretion ,10,11,12The pancreatic acinar cells are normally responsible for synthesizing, processing, and secreting huge quantities of digestive enzyme proteins that require folding and processing in the endoplasmic reticulum (ER) for appropriate transportation to the cell organelles for secretion upon physiologic stimulation. Studies have suggested that chronic alcohol consumption increases the mRNA levels of pancreatic digestive enzymes  but impaChronic pancreatitis (CP) can result from recurrent episodes of acute pancreatitis (RAP) which results in permanent structural and functional damage and a high risk for pancreatic cancer development ,26,27. AMeta-analysis of observational studies have shown a dose-response relationship between average alcohol consumption and the risk of pancreatitis in men and women, and defined some thresholds required for increased risk of CP and RAP ,31. Othe(i)Metabolic basis for alcoholic pancreatitis(ii)Role of the UPR in the development of alcoholic pancreatitis(iii)Role of impaired autophagy in the pathogenesis of alcoholic pancreatitis(iv)Chronic alcohol consumption dysregulates pancreatic endocrine function and exacerbates metabolic alterations in people living with human immunodeficiency virus (HIV)In this review we discuss the recent advances in understanding the complexity of alcohol-induced pancreatic dysfunction and development of alcoholic pancreatitis under the following pathophysiological themes:About 90% of the ingested ethanol is metabolized oxidatively in the liver by cytosolic alcohol dehydrogenase (ADH) and microsomal cytochrome P450 2E1 (Cyp2E1) to acetaldehyde, which is further metabolized to acetate by mitochondrial aldehyde dehydrogenase. Acetaldehyde is a reactive aldehyde and can alone cause oxidative stress in the target tissue. During chronic alcohol ingestion, ADH activity is commonly reduced in experimental animals and human subjects ,39,40, aThe metabolic capacity to oxidize ethanol in the pancreas is much lower compared to the liver . HoweverThe relative role of oxidative and non-oxidative metabolites of ethanol during chronic alcohol abuse in inducing pancreatic damage is not well understood. It has been reported that the oxidative metabolism of ethanol sensitizes the pancreas and promotes cell damage in acinar cells ,47. In a−) deer mice were utilized [− and hepatic ADH normal (ADH+) deer mice were fed daily for two months a liquid diet containing 1, 2 or 3.5 g% ethanol, doses relevant to those consumed by alcoholic subjects. A dose-dependent onset of lipid phenotype along with ~5-fold increases in FAEE levels in the pancreas were seen in ADH− vs. ADH+ deer mice fed with 3.5 g% ethanol [− deer mice but not in ADH+ mice when these mice were fed 3.5 g% ethanol for four months [− deer mice revealed significant ER stress as evidenced by swelling and disintegration of ER cisternae in acinar cells, and activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK) branch of the UPR for ER stress [The large amounts of highly lipophilic FAEEs that accumulate in the pancreas after acute and chronic ethanol exposure ,42,55 hautilized . ADH− an ethanol . Furtherr months . The incR stress .The time and concentration-dependent formation of FAEEs and the cytotoxicity of ethanol exposure has also been demonstrated in rat pancreatic exocrine tumor (AR42J) cells  and in iAcinar cells are specialized in the production, storage, and secretion of digestive enzymes and other proteins. To enable this high rate of protein production, acinar cells have extensive ER networks. The ER regulates the folding, processing, and trafficking of all secretory and membrane proteins, as well as the degradation of permanently misfolded/unfolded proteins by autophagy and the ubiquitin system. ER homeostasis is modulated by the UPR, a signaling program activated when the ER fails to properly process proteins, a condition termed ER stress ,61. The Chronic alcohol feeding in rodents does not cause pancreatitis but increases levels of XBP1s in the pancreas, an effect likely due to ethanol-induced oxidative stress and with many potential consequences. XBP1s control transcription of many chaperones and oxidoreductases required for ER disulfide bond formation and folding of digestive enzymes, as well as components of protein degradation systems designed to degrade misfolded proteins. In acinar cells, XBP1s also have UPR independent functions and regulate post-ER protein trafficking and secretion, mitochondria-ER and lysosomal-ER communication, ER-dependent autophagy, and secretory vesicle formation ,20. GeneDue to epidemiologic observations that smoking augments the effects of alcohol abuse on pancreatitis ,31, one These studies indicate that, while alcohol alone can cause ER protein folding disorders, the adaptive UPR processes with alcohol abuse maintain ER homeostasis and prevent pancreatitis responses in the acinar cell. However, additional stresses such as smoking and possibly genetic mutations in digestive enzymes folded within the ER can incapacitate or overwhelm the adaptive and protective UPR resulting in a pathologic UPR and pancreatitis. Agents that attenuate ER stress are being tested in experimental models to determine potential benefits to treat pancreatitis in humans.Autophagy is a cellular degradative process that requires the formation of double membrane autophagosomes that carry autophagic cargoes to lysosomes for degradation. Lysosomes sit at the end stage of the autophagic process and play a critical role in the completion of the autophagy process (or autophagic flux). Thus, it is critical to maintain the number and quality of lysosomes to meet the needs of autophagic degradation in response to various types of stresses. Lysosomal biogenesis is regulated by a family of proteins belonging to the microphthalmia family of basic helix-loop-helix-zipper (bHLH-Zip) transcription factors (MiT family) , which iEmerging evidence implicates an impaired autophagy-lysosomal pathway in the pathogenesis of pancreatitis ,82,83. AIt was recently demonstrated that in an experimental pancreatitis mouse model, cerulein decreased pancreatic TFEB proteins and TFEB-mediated lysosomal biogenesis, causing decreased lysosome numbers and insufficient autophagic flux . Mice wiUsing the chronic feeding plus binge (Gao-binge) alcohol model, two laboratories recently reported that alcohol increased levels of serum amylase and lipase ,89. Gao-In addition to the vast data on the risk for alcohol-mediated effects on pancreatitis development, there is increasing evidence that chronic alcohol consumption also impairs endocrine pancreatic function. Clinical ,93,94 anClinical studies have shown that alcohol decreases circulating basal insulin secretion , and cirThe metabolic stress mediated by alcohol, including a chronic inflammatory milieu, oxidative stress, and mitochondrial dysfunction leads to islet cell dysfunction and could result in the decreased key transcriptional factors regulating islet cell function. Increases in blood glucose increase the transcription of the insulin gene . The canThe detrimental effects of chronic alcohol consumption on pancreatic function is enhanced under comorbid conditions such as viral infections. The prevalence of alcohol use disorder (AUD) in people living with HIV (PLWH) is higher than the prevalence of AUD in the general population ,117. AntStudies in SIV-infected macaques have shown that chronic binge alcohol (CBA) alters metabolic homeostasis ,119,120.Thus, increasing clinical and preclinical evidence points to alcohol-induced pancreatic endocrine dysfunction, increasing the risk for metabolic comorbidities. Further studies are warranted to understand the crosstalk between the pancreas and other organs such as the gut, adipose tissue, and skeletal muscle that could potentially contribute to pancreatic endocrine dysfunction. Whether lifestyle modifications including exercise or diet interventions can improve pancreatic function directly or indirectly by improving muscle and adipose health should be examined. Moreover, continuing to gain a better understanding of how alcohol-mediated alterations in epigenomic mechanisms impair pancreatic function, both exocrine and endocrine, is likely to identify targets for therapeutic interventions.Overall, this review on the metabolic basis of ethanol-induced pancreatic cell injury provides valuable information for a better understanding of mechanisms of pancreatic insufficiency and pancreatitis pathogenesis such that appropriate therapeutic strategies could be developed. Based on these considerations, it is predicted that agents that can reduce ER stress and improve autophagic mechanisms may be beneficial for preventing or treating pancreatitis. Further, lifestyle modifications including exercise or diet interventions could also improve both exocrine and endocrine pancreatic function.


Substantially altered gastrointestinal anatomy/physiology after bariatric surgery presents new challenges for the proper medication management of these patients; drug absorption and bioavailability may increase, decrease, or remain unchanged post surgery, depending on the specific drug in question and the type of bariatric procedure. In this article, we offer a concise overview of the various aspects of this clinically significant issue, aiming to provide readers with a clear understanding as well as practical tools to handle drug management post bariatric surgery. Realizing the potentially altered pharmacokinetics of various drugs after bariatric surgery is essential for providing optimal pharmacological therapy and overall patient care. The global rise of the obesity epidemic is amongst the toughest challenges we face. The many comorbidities associated with severe obesity  have turned this disease into the second most common factor contributing to preventable death (second only to tobacco) . The priThis rapidly growing population of bariatric patients presents new challenges to the field of oral drug therapy . SubstanTo date, the most commonly performed bariatric procedures are the sleeve gastrectomy, the single-anastomosis gastric bypass, and the Roux-en-Y gastric bypass (RYGB) . While tPharmacokinetic alterations of oral drugs after bariatric surgeries may occur in many different mechanisms. After being swallowed, solid immediate-release drug products have to disintegrate and be broken down into small particles. This process typically happens in the stomach, and since all bariatric procedures involve significantly reduced stomach size and contractility, tablets may fail to adequately disintegrate after bariatric surgery. Similarly, drug dissolution in the GI is a prerequisite for subsequent absorption, and for many drugs with borderline solubility, the reduced stomach size (and hence fluid intake) and contractility may result inadequate drug dissolution. Moreover, the solubility/dissolution of many drugs is pH-dependent and the increased gastric pH after bariatric surgeries  may further alter their dissolution. After gastric emptying into the duodenum, lipophilic drugs may require bile and pancreatic secretions for solubility/dissolution , while iGeneral recommendations for oral drug therapy after bariatric surgery have been outlined in guidelines ,26. FirsAltogether, the complexity described in this article, along with the substantial inter- and intrapatient variability in drug absorption post surgery, and the limited data available on this subject emphasize the urgent need for further research in order to reveal the optimal oral drug therapy after bariatric surgery. All medical staff must be aware of this critical concern, including physicians, pharmacists, nurses, and dieticians, so the short- and long-term safety and efficacy of bariatric patients’ drug regimen can be ensured.


Dialictus sweat bees, indicating that some bee species benefitted from environmental conditions present during the drought. The impact of drought on the composition of bee samples was three fold higher than the impact of habitat fragmentation, and habitat fragmentation did not appear to have exacerbated the impacts of drought. Our findings highlight the importance of studying how impacts of climate change compare with impacts of habitat loss and other threats to biodiversity conservation.Global climate change is causing more frequent and severe droughts, which can have serious impacts on our environment. To examine how a severe drought in 2014 impacted wild bees in scrub habitats of San Diego, California, we compared bee samples collected before and after the drought. We also investigated whether habitat loss and fragmentation worsened the impacts of drought on wild bees by comparing samples collected from large natural reserves to those from small fragments of scrub habitat embedded in urban areas. Samples collected after the drought contained fewer bee species and fewer individual bees of most species, indicating that bee populations suffered losses during the drought. However, after-drought samples contained large numbers of Lasioglossum subgenus Dialictus increased in abundance after the drought, driving increased representation by small-bodied, primitively eusocial, and generalist bees in post-drought assemblages. Conversely, among non-Dialictus bees, post-drought years were associated with decreased abundance and reduced representation by eusocial species. Drought effects were consistently greater in reserves, which supported more bee species, than in fragments, suggesting that fragmentation either had redundant impacts with drought, or ameliorated effects of drought by enhancing bees’ access to floral resources in irrigated urban environments. Shifts in assemblage composition associated with drought were three times greater compared to those associated with habitat fragmentation, highlighting the importance of understanding the impacts of large-scale climatic events relative to those associated with land use change.Global climate change is causing more frequent and severe droughts, which could have serious repercussions for the maintenance of biodiversity. Here, we compare native bee assemblages collected via bowl traps before and after a severe drought event in 2014 in San Diego, California, and examine the relative magnitude of impacts from drought in fragmented habitat patches versus unfragmented natural reserves. Bee richness and diversity were higher in assemblages surveyed before the drought compared to those surveyed after the drought. However, bees belonging to the  Climate change is considered one of the leading threats to biodiversity worldwide ,2,3, witPlant-pollinator mutualisms are an example of a key biological interaction that may be vulnerable to the effects of drought (reviewed in ). DuringHere, we report on a dataset of native bees (Hymenoptera: Anthophila), collected from endangered coastal sage scrub habitats in San Diego County, California, that fortuitously spanned a severe drought event in the year 2014 ,20. NatiUsing this dataset, we test the hypothesis that the reduction of floral resources during the drought event negatively impacts the survival and reproduction of native bees. Accordingly, we predict that observed bee richness and abundance would be lower in the years immediately following the drought, compared to the years before the drought, as a result of local extirpations and population declines. Additionally, we also hypothesize that bee species may be differentially impacted by drought as a function of their life history traits. Of the many axes of life history variation exhibited by bees in our system, we focus our inquiry on three traits that may be drivers of bee species’ responses to drought.First, bee species vary with respect to their diet breadth, where some species specialize on the pollen of a narrow set of plant species or families, while others utilize pollen from numerous botanical families. Generalist  species tend to be less susceptible to environmental perturbations in general ,24,25, lSecond, bee species vary with respect to their degree of sociality. While the majority of species in our system are solitary in the broad sense , several genera consist at least in part of primitively eusocial species, which form annual colonies founded by a single queen produced by the previous generation. Eusocial species may perform poorly relative to solitary species in years of reduced resource availability because of their higher sensitivity to resource gaps during their long colony lifetime ,28. HoweThird, bee species in our system span at least an order of magnitude in body length . Given tAs the above discussion demonstrates, life history traits have the potential to either enhance or reduce bee species’ ability to withstand droughts. Thus, understanding how the potential tradeoffs of each life history trait translate into realized population dynamics in drought scenarios necessitates examining empirical, assemblage-wide data. Empirical examination is especially important in systems such as ours, which may include both xeric-adapted and mesic-adapted bee species , which The impacts of drought on our system may not act in isolation, as drought has been known to interact with other forms of anthropogenic perturbations to produce synergistic impacts on ecosystems and biological communities ,33. In oData collection occurred in coastal sage scrub (CSS) habitats in San Diego County, CA, USA. San Diego, along with the rest of southern California, is a global biodiversity hotspot for both vascular plants  and natiwww.weather.gov) that preceded and immediately followed the single worst year of drought in 2014 [Bee assemblage data considered in this study were collected as part of a series of previous studies investigating the effects of habitat fragmentation on native bee diversity ,22. We c in 2014 ,20. Not During the peak blooming season of CSS flora (March–August), we deployed colored bowl traps to collect native bees in our study plots. We generally sampled bees at 2–3 plots per day and on 3–4 days per week as weather conditions permitted, with the average sampling frequency each year  depending largely on the number of plots sampled, additional data collection goals, and availability of field assistants. Bowl traps consisted of bright white, 96-mL plastic bowls 7 cm in diameter, painted fluorescent blue or yellow or left unpainted, and filled with 60 mL of unscented detergent solution. Bowl traps were deployed from ca. 0800 h to ca. 1600 h on each survey day, in roughly linear transects containing 15 bowls each (5 of each color), with nearest bowls placed 5–10 m apart. In 2011 and 2012, we deployed two bowl transects  per study plot during each survey, whereas in 2015 and 2016, we deployed a single bowl transect  per study plot during each survey. Although bowl traps are known to exhibit bias with respect to the composition and relative abundance of bee species sampled , thiBombus, Augochlorella, Halictus, and many Lasioglossum species, in particular species of subgenus Dialictus). Cleptoparasitic species, which invade the nests of pollen-collecting species and lay their eggs therein such that their larvae usurp the nest provisions, were assigned a unique category for both diet breadth and sociality. Nearly all eusocial bee species are polylectic [Apis mellifera L.), which was the numerically dominant bee species in our system [All native bees collected in the bowl traps  were washed, dried, mounted, labeled, identified, and databased. The vast majority of individuals  were identified in previous studies ,22 to onlylectic , includir system  and the Bee assemblages are strongly influenced by the local composition and blooming phenology of plant species ,55. ThusWe performed two sets of analyses to investigate additive and interactive impacts of drought and habitat fragmentation on the studied bee assemblages. We used univariate analyses to examine how diversity, abundance, and proportional representation of different functional traits differed across bee assemblages. We used multivariate analyses to examine the joint impacts of drought and habitat fragmentation on bee assemblage composition. We performed all analyses using program R, version 3.6.3 .lme4 package [H), body size (approximated using intertegular distance), and the proportional representation of individuals belonging to polylectic species  and primitively eusocial species. To account for the fact that the number of survey days and the number of individuals collected varied across study plots and study years, we estimated species richness and Shannon-Wiener diversity by interpolating or extrapolating assemblages [iNEXT package [Univariate analyses: We constructed generalized linear mixed models (GLMMs) using the  package  to examiemblages  to a com package , which u package  to generlmerTest package [emmeans package [All GLMMs include fragmentation status (scrub fragments versus unfragmented reserves), drought status (before (2011–2012) versus after (2015–2016)), and their interaction as independent variables; study plot identity and study year (the latter nested within drought status) were random-intercept terms. The locations of two study plots in CSS reserves were shifted slightly between 2012 and 2015 see ; however package  to deter package  to perfoWe analyzed blooming plant species richness  pooled across all sampling dates in each plot within each year using a Gaussian GLMM (link = identity). We analyzed bee abundance using a Poisson GLMM (link = log), with the number of transect-days  included as an offset variable such that the model effectively examines differences in numbers of bees collected per transect-day. We analyzed species richness, Shannon-Wiener diversity, and average body size using Gaussian GLMMs. The proportional representation of individuals belonging to eusocial species and to polylectic species were analyzed using binomial GLMMs (link = logit), which use the ratio of the numbers of individuals belonging to the target versus non-target state  as the dependent variable.Lasioglossum subgenus Dialictus , which accounted for the majority of individuals belonging to species that are small-bodied, polylectic, and eusocial. We also constructed a Poisson GLMM to examine Dialictus abundance. Further, to investigate the extent to which this group may have driven our other univariate results, we repeated our analyses that examined bee abundance, body size, diet breadth, and sociality after excluding all Dialictus individuals from our dataset. These additional models for non-Dialictus bee assemblages were structured identically to their counterparts constructed using the full dataset.Upon evaluating the results of our models for body size and proportional representation of eusocial and polylectic species, we decided to construct an additional binomial GLMM to examine the proportional representation of individuals belonging to vegan package [Multivariate analyses: We performed a permutational multivariate analysis of variance  and per package . To contpairwiseAdonis package [As there is currently no mixed-effects framework available for PERMDISP and PERMANOVA, we used study year rather than drought status as an independent variable in these analyses. Since PERMDISP does not accommodate the inclusion of multiple independent variables, we performed three distinct analyses to examine whether or not the beta diversity of bee assemblages differed across (i) levels of fragmentation status, (ii) study years, and (iii) treatment combinations . PERMANOVA, on the other hand, does accommodate multiple independent variables, so we included fragmentation status, year, and their interaction in this analysis. We used the  package  to perfot = 3.21, p = 0.003) (p > 0.05). On the other hand, bee species richness was reduced post-drought relative to pre-drought as predicted . Bee diversity exhibited the same trend as species richness , except that the reduction of diversity post-drought in reserves was only marginally significant ; however, there was a significant interaction between drought status and fragmentation status (Gaussian GLMM = 0.003) b. In con= 0.003) a and exhredicted b, althounificant .z = 2.33, p = 0.020). The proportional representation of individuals belonging to primitively eusocial species increased after drought, .With respect to the impacts of drought and habitat fragmentation on the life history trait distributions of bee assemblages, the proportional representation of individuals belonging to polylectic species was higher post-drought than pre-drought d, with tdrought, e, while drought, f. In botLasioglossum subgenus Dialictus  increased after drought . In contrast, the abundance of non-Dialictus bees decreased after the drought in both reserves and fragments . The proportional representation of eusocial bees among non-Dialictus individuals was lower post-drought only in fragments . Lastly, among non-Dialictus bees, both the proportional representation of polylectic bees and average body size did not differ between pre- and post-drought for either reserves or fragments  and between reserves and fragments , there was no significant interaction between the two variables . Based on R2 values, study year explained more than three times the amount of variation in the data compared to fragmentation status. Post-hoc tests revealed that bee assemblages in study years with the same drought status differed little, if at all, from each other, while pre- versus post-drought comparisons revealed strong differences in bee assemblage composition , between reserves and fragments , or across treatment combinations .Unlike the results of the univariate analyses, multivariate analyses revealed only additive effects of drought and habitat fragmentation on bee assemblage composition . Althougposition . On the Lasioglossum subgenus Dialictus). In every assemblage-level univariate comparison, we observed differences in pre- versus post-drought assemblages in reserves, and often in fragments as well. Dissimilarity-based, multivariate analysis also revealed strong differences in bee species composition between pre- and post-drought assemblages.Our analyses revealed strong impacts of drought on bee assemblages in the fragmented coastal sage scrub of San Diego. Post-drought bee assemblages had fewer species, were greater in abundance, and were more strongly represented by individuals belonging to eusocial, polylectic, and smaller-bodied species  nigrescens (Crawford) and Halictus tripartitus Cockerell) also did not decrease after the drought , in contrast to the post-drought declines exhibited by the rest of the non-Dialictus bee assemblage  of the overall bee fauna in the following years. The absence of pre- versus post-drought differences in the mean body size of non-Dialictus bees perhaps suggests that neither mobility nor resource requirements are chief drivers of bee species’ response to drought events, unlike their role in modifying the response of bees to habitat fragmentation [Dialictus bees suggests that specialists may not be disproportionately impacted by drought. Pollen specialists may withstand drought by associating with drought-hardy plant species, or by evolving more finely-tuned synchronization of phenologies with their host plants, including greater propensity to aestivate through drought years when environmental conditions prohibit their host plants from blooming [Dialictus eusocial bees in fragments after the drought event suggest that for the rest of the eusocial taxa, heightened requirements for ample and consistently available food resources [Dialictus species in our system exhibits solitary life history atypical for the subgenus) indicate that a nuanced approach must be taken when attempting to understand and predict the response of bees to environmental perturbations based on examinations of single functional traits.The increased abundance of emblages . The decentation . Similarblooming ,26 (but blooming ). Lastlyesources ,28 may hDialictus species, 2R value of study year is nearly 3.5 fold higher than that of fragmentation status  and those that cannot , our results should be interpreted with caution. Future data collection during drought events in our system is needed to fill the knowledge gap regarding the identities of bee species that can remain dormant to avoid droughts, and, in the event of multi-year droughts, the number of consecutive years such species may remain dormant. Such knowledge may be critically necessary for proper interpretation of data collected in large-scale efforts to monitor bee populations , as thes . Howevetus bees b,c seem The severe drought event in 2014 had profound impacts on bee assemblages that were, in many cases, more acute than the impacts of habitat loss and fragmentation. Thus, future conservation efforts aimed at preserving at-risk bee populations and maintaining available pollination services may need to focus on mitigating the impacts of climate change at least as much as those of habitat loss. More long-term monitoring of bee assemblages spanning drought events of differing durations will be necessary to fully appreciate the potentially diverse responses of different bee species to the challenges brought about by drought and its impacts on the biotic and abiotic environment. The ability to better predict shifts in the activity and population dynamics of bee assemblages in response to extreme climate events will be helpful in guiding efforts to conserve the bee taxa that are most sensitive to the joint impacts of drought and habitat fragmentation in our system and other hotspots of bee diversity threatened by similar pressures.


Testicular trauma is common, usually trivial and rarely requires hospital attendance, but if it does, then imaging becomes essential as scrotal assessment may be difficult due to pain and/or scrotal disruption. Ultrasound (US) assumes a crucial role as other cross-sectional modalities have a limited use in the acute presentation. Despite the acceptable accuracy of conventional US techniques, there are limitations which hinder a thorough evaluation, critically the assessment of tissue viability, crucial for clinical management and prognosis. Contrast-enhanced ultrasound (CEUS) has been shown to offer improved flow visualisation and tissue perfusion compared with conventional Doppler techniques. CEUS can accurately and confidently demonstrate the viability of testicular parenchyma, delineate fracture lines and haematomas and guide treatment for testis-sparing surgery or orchidectomy. The purpose of this review is to present the literature, familiarise physicians with the principles of CEUS and findings of scrotal trauma and illustrate the main abnormalities through characteristic and educative cases. CEUS is a portable, cost-effective, quick and safe tool which can assist with planning of testis-sparing surgery and overall treatment planning of patients sustaining scrotal trauma.CEUS is more sensitive than colour Doppler US in visualising tissue vascularity, establishing tissue viability and avoiding unnecessary emergency surgery or orchidectomy.CEUS is valuable in diagnosing sequelae of testicular trauma such as intra-testicular haematomas, fractures, rupture, ischaemia and extra-testicular haematoma.Scrotal injury is common but rarely results in hospital presentation and makes up 1% of all trauma, most commonly occurring in the first three decades of life . Most caClinical assessment following scrotal trauma is often limited due to scrotal pain and swelling. Therefore, imaging is the cornerstone for diagnosing traumatic scrotal injury and guiding the treatment plan between conservative versus operative management. Cross-sectional imaging techniques (computed tomography and magnetic resonance imaging) are either impractical or inconclusive in the setting of scrotal trauma , 4. UltrTM, Bracco, Italy) used in CEUS examination are non-nephrotoxic, the phospholipid shell being metabolised by the liver and the sulphur hexafluoride gas component being exhaled through the lungs. The technique can be performed in patients with renal impairment and needs no prior laboratory testing. Moreover, UCA have a lower risk of adverse reactions compared to the contrast agents currently used in computed tomography (CT) and magnetic resonance imaging (MRI) [Contrast-enhanced ultrasound (CEUS) has gained increasing popularity worldwide as an imaging technique, particularly following the Food and Drug Administration (FDA) approval in paediatric and adult use in focal liver lesions . The abing (MRI) –15. CEUSng (MRI) –13. In tng (MRI) , 16–18.CEUS has the potential to become an indispensable tool in the assessment of acute scrotal trauma, providing significantly improved levels of accurate and diagnostic imaging , 19, helCEUS is most commonly performed using an UCA consisting of 3–5 μm sized microbubbles of sulphur hexafluoride gas encapsulated in an outer phospholipid shell (SonoVue) , 21. DueThe technique for CEUS of the acute scrotum needs to be adjusted to preserve maximum patient comfort and diagnostic quality . The patInitial B-mode US is undertaken in the conventional manner, and high-frequency linear transducer ranging between 7 and 15 MHz is used. The examination of the testis should include checking the integrity of tunica albuginea and paratesticular tissues such as the epididymis, scrotal wall and the presence of fluid. B-mode US should be always complemented with colour or power Doppler US in order to assess tissue vascularity, a finding relevant to establish tissue viability.For CEUS examination, the patient will require intravenous access for contrast administration. It is often helpful to undertake the CEUS examination with a split screen approach, with B-mode and CEUS images displayed sided by sided, allowing low MI and lower quality B-mode image to localise the area of interest. An alternative is to have a contrast-specific image overlaid on a low MI B-mode image. These techniques may not be necessary for global abnormalities such a complete testicular infarction. While CEUS has an excellent safety profile , 13, anaNormal testicular parenchyma is homogenous with an echogenic surface line indicating the tunica albuginea. On CEUS, the testis should enhance homogeneously with a striated pattern Fig.  represenIntratesticular haematoma is an uncommon finding in scrotal trauma, although the true incidence may be underreported as patient may be asymptomatic. A variety of ultrasound findings are seen depending on when the scan is performed in relation to when the traumatic event occurred . Acute h, the visualisation of homogenous enhancement of the entire testis on CEUS negates the need for further investigation  is typical of a pseudoaneurysm  and can Presence of blood between the layers of the tunica vaginalis is defined as a haematocele , 27 and In the presence of an acute echogenic haematocele, it is difficult to examine the integrity of the tunica albuginea, limiting the assessment for associated testicular rupture. CDUS assessment of the testis in the setting of surrounding haematocele can be limited, often leading to surgical exploration. However, CEUS offers increased diagnostic yield with regards to identifying parenchymal borders, infarction and tunica albuginea integrity, and differentiating a surrounding haematocoele Fig.  6, 7, 2, 27, 25.In cases of a simple haematocele, CEUS will demonstrate uninterrupted tunica albuginea and no enhancement of the haematocele . FurtherExtratesticular haematomas can originate from a variety of sources from within the scrotum, but also may traverse a patent inguinal canal from the abdomen into the scrotal sac . As a reWhilst the use of CEUS is established in other clinical contexts, use in testicular trauma is less well recognised. CEUS improves the diagnostic accuracy and confidence over conventional B-mode US and CDUS in detecting viable testicular parenchyma after scrotal trauma which is clinically significant in potentiating testis-sparing surgery. CEUS could also play a vital role in helping detect findings which allow conservative treatments and negate unnecessary exploratory surgery or orchidectomy.


The COVID-19 pandemic has had a devastating global impact, with older adults being most at risk of death from the disease. However, acute sarcopenia occurs in survivors of COVID-19; older adults and the most critically unwell patients are the most at risk. Acute sarcopenia is an under-recognised condition of acute muscle insufficiency, defined by declines in muscle function and/or quantity within six months, usually following a stressor event. This commentary reviews definition and mechanisms of acute sarcopenia in COVID-19 and suggests recommendations for research and clinical practice. Research should now focus on the longer-term consequences of acute sarcopenia in patients who have suffered from COVID-19. At the same time, clinicians need to be increasingly aware of the condition, and measurements of muscle strength, quantity, and physical performance should be embedded into clinical practice. Clinicians should consider the risks of acute sarcopenia when weighing up the risks and benefits of treatment (e.g. dexamethasone), and instigate multidisciplinary treatment including dietetics input. Sarcopenia is a condition of extreme muscle insufficiency , definedSarcopenia is common in hospitalised populations -12 and aMuscle loss in acute sarcopenia is due to an imbalance in muscle homeostasis with increased muscle degradation and reduced muscle synthesis. Muscle degradation is a term which broadly describes the loss of muscle via both reduction in muscle fibre size (atrophy) and reduction in the number of muscle fibres (hypoplasia). Hypoplasia is believed to occur secondary to motor neurone death and muscle fibre denervation and atrophy secondary to proteolytic pathways . Older aUnfortunately, measurement of muscle strength or muscle quantity are not currently fully integrated into routine clinical care, although anthropometry may be performed as part of a dietetics assessment . TherefoCoronavirus disease 2019 (COVID-19) is a severe acute infectious disease caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) . The gloCOVID-19 is known to be associated with significant systemic inflammation and a subset of patients will experience a severe cytokine response. Serum concentrations of inflammatory cytokines including Tumour Necrosis Factor Alpha (TNF-α) have been shown to be higher in patients with COVID-19 requiring critical care treatment . This haVitamin D deficiency has been implicated in sarcopenia; muscle biopsies from individuals with vitamin D deficiency have shown atrophy of Type II muscle fibres . VitaminObesity has been demonstrated as an adverse prognostic factor in COVID-19, being associated with increased risk of hospitalisation, critical care admission, and mortality . ObesityThe most marked individual declines in muscle function in hospitalised patients with COVID-19 were seen in patients who required admission to critical care , relatinAs described, research suggests that heightened inflammation in COVID-19 is associated with catabolic states and anabolic resistance, leading to increased nutritional demand, particularly protein. Despite this, many patients with COVID-19 struggled to meet even basic requirements. Loss of sense of taste or smell are recognised symptoms of COVID-19, that may occur in up to two thirds of cases . This leImportantly, many patients hospitalised with COVID-19 suffered prolonged periods of bedrest and reduced physical activity. Depending on hospital models, this may have been further exacerbated by isolation policies preventing mobilisation outside of smaller ward areas or side rooms. Even in those who did not require hospitalisation, there is evidence that patients who contracted COVID-19 suffered from immense fatigue. This is likely to have reduced their physical activity . During The effect of treatment initiated for COVID-19 should also be considered. The Randomised Evaluation of COVID-19 Therapy (RECOVERY) trial demonstrated a survival benefit with dexamethasone, particularly when given to the most unwell patients . HoweverPrevious research completed in patients with Acute Respiratory Distress Syndrome has demonstrated a decrease in lean muscle mass during the year following discharge from critical care . This suResearch that aims to characterise changes in muscle quantity, quality, and function in hospitalised patients with COVID-19 and other conditions  is imperAt the same time, clinicians need to be increasingly aware of the problem of acute sarcopenia. Where possible, clinicians should integrate serial measurements of muscle strength, physical performance, and muscle quantity into their clinical practice, enabling them to identify early when there is a change, and assess responsiveness to treatment and therapy. Without any form of monitoring, acute sarcopenia will not be identified until clinically extreme. Muscle strength can be measured using a dynamometer, where available; assessment of chair stands is an alternative where a dynamometer is not available and the patient is able to sit in a chair . UltrasoIn any care model for patients suffering from or recovering from COVID-19, treatment needs to enlist a multidisciplinary approach . Early dAcute sarcopenia is a condition of severe acute muscle insufficiency that normally occurs following a stressor event; COVID-19 is a particularly aggressive insult. Further research is needed to help characterise this condition and understand the longer-term consequences. This will enable the development of targeted interventions. Meanwhile, clinicians should be aware of this condition within their own practice and seek early multidisciplinary team involvement.


Kidney stone disease is not only a pathology of the urinary tract, but it is also closely associated to metabolic abnormalities and incorrect dietary habits. Rodrigues et al.,Insulin resistance increases the risk of kidney stone formation through changes in metabolism and transport of the kidney tubule cells. Actually, insulin resistance impairs the renal acidification process, namely ammonium production from L-glutamine in the proximal tubule cells, lowering urinary pH and citrate excretionHealthy dietary patterns, as the DASH or Mediterranean diet, represent a population-based substantial approach able to reduce the risk of cardiovascular events. The diets are rich in fruits, vegetables, whole grains, and low-fat dairy foods; lean meat, fish, poultry, nuts, and beans are abundant whereas red meat, added fats, processed foods, high-salt foods, and sugar-sweetened foods and beverages are limited. The healthy dietary pattern represents a lifestyle that also includes not smoking and physical activity. Both Mediterranean and DASH diets are rich in vegetables. A plant-based diet raises the concern of high intake of oxalate. Noori et al. performed a small study where participants were randomly assigned to receive a DASH or a low-oxalate diet. They found a trend towards an increase in urinary oxalate excretion but also a trend towards a reduction in calcium oxalate supersaturation in the DASH versus the low-oxalate diet group. This occurred because of an increased magnesium and citrate excretion and a higher urine pH in the DASH diet subjectsA DASH diet may lower the risk of kidney stone formation by increasing urinary citrate excretion and urine volume. A weak association between higher DASH intake and lower urine relative supersaturation was found, so a possible role of unidentified stone inhibitors in dairy products and/or plants was suggestedRodrigues et al. reported also that the diet of kidney stone formers showed a higher amount of protein and salt but lower calcium than in controlsHigh consumption of proteins, especially of animal origin, leads to increased urine excretion of calcium, oxalate and uric acid, and lower urine pH and citrate: all of these changes lead to a pro-lithogenic profile. Plant-origin proteins exert much less effects on these parameters: one more reason to prefer a plant-based diet. Dietary sodium load causes an increase in urinary calcium excretion. Thus, a restriction of dietary salt intake  should be suggested for primary and secondary prevention of calcium stone formation. A low calcium intake 400-500 mg/day) may decrease calciuria in calcium stone formers but it increases urine oversaturation of calcium-oxalate due to the increase of oxaluria coming from increased intestinal absorption. Therefore, a diet with a calcium content ≥1g/day is preferable, apart from a condition of diet-dependent hypercalciuria. Finally, a comprehensive dietary approach should include also interventions aiming to prevent or correct conditions that cause metabolic changes as overweight or obesity, dyslipidemia, diabetes, hypertension, etc00 mg/dayIn conclusion, the findings of Rodrigues et al. in Brazilian kidney stone formers confirm that metabolic syndrome and unhealthy dietary patterns are associated with kidney stone formation. This warns us that it is time to implement a more extensive metabolic assessment and correct nutritional imbalances in the clinical management of kidney stone patients. Promoting a healthy dietary pattern could be the first population-based intervention as a primary prevention strategy to reduce the risk of kidney stone formation and cardiovascular events. Patient-based nutrient-specific dietary manipulations can be added in a secondary prevention setting after the assessment of cardiovascular and kidney stone risk factors.


Establishment of gastric organoids derived from primary gastric tissues and pluripotent stem cells or embryonic stem cells characterizes niche factors required by the gastric stem cell populations, and further provides new insights into stomach development, host-Helicobacter pylori interactions and malignant transformation. Furthermore, focus on the gastric stem cells and their niches uncovers the initiation of stomach precancerous lesions and origin of gastric cancer, providing options for cancer prevention and intervention. In summary, with the development of stem cell research, gastric stem cells give us more opportunities to prevent and treat stomach diseases.Gastric epithelium operates in a hazardous environment that curtails the lifespan of the constituent cells, imposing a requirement for continuous epithelial renewal. Stem cells that reside in the stomach are thus essential for regulating physiological tissue renewal and injury repair because of their self-renewal, high proliferation capacity and multiple differentiation potentials. Recent investigations using lineage tracing models have identified diverse populations of gastric stem cells and even fully differentiated cells that can regain stem cell capacity, so enriching our understanding on the identity and plasticity of gastric stem cells. These cell populations include the Villin promotor, Lgr5 Although some sporadic reviews on this topic have been published in past years  transcript, Mist1 and Troy  may be as the candidate of the adult stem cell markers in the oxygenic mucosa. Lineage tracing demonstrated that TFF2 mRNA-expressing cells above the neck region are the progenitors for mucus neck, parietal and chief cells but not for pit or ECL cell lineages in the corpus , while TCL cells . In vitrn single . This evic units . This re+ cells in the pylorus (Some biomarkers are shared among gastric stem cells in both pyloric and corpus glands. Sox2 (Sex-determining region Y box protein 2)-positive cells are found in both the pylorus and corpus of the glandular stomach in mice, although no apparent overlap exists with Lgr5 pylorus . Cells l pylorus . Lrig1  and bone morphogenetic proteins (BMPs) signaling pathways. These have been found to exert important effects on gastrointestinal development and differentiation . In the ntiation . In the ntiation . Additiontiation , and epintiation . Antral receptor , corpus  pathway . Wnt pat pathway .+ endothelial cells and Cxcr4+ innate lymphoid cells contributed to the corpus stem cell niche partly through production of Wnt5a from innate lymphoid cells   .Despite the importance of these growth factors and cell components in gastric stem cell niches, the identity of cells providing this niche factors and their interactions remain elusive. Meanwhile, knowledge about the niches surrounding the base of corpus gland is also not clear. Further efforts are needed to characterize the various components involved in the gastric stem cells niche and thus in gastric stem cell biology, in order to elucidate their roles in the regulation of gastric epithelium homeostasis.in vitro reconstitution of this specific niche has led to the development of gastric stem cell culture. Some simplified techniques have been developed to build in vitro models to investigate stomach stem cells. For instance, Yang et al. built a gastric epithelial cell clone (named KMU-GI2) with sustained growth in a low-calcium medium supplemented with N-acetyl-L-cysteine and L-ascorbic acid 2-phosphate . They observed that gastric spherical clones on the surface of gastric fibroblasts grow in a single layer. Those spherical cells harbored molecular markers capable of spontaneously differentiating and were unique to gastric stem cells. Nonetheless, these above models cannot achieve pure and long-lived culture in vitro after a number of cells divisions, and whether the identity of stem cells would be changed or not in this culture system is not well determined.Regarding the importance of these niche factors, hosphate . These c+ cell isolated from the gastric glands of Lgr5-EGFP-ires-CreERT2 mice were capable of generating a single-layered epithelial structure, that was then called the gastric organoid. This in vitro culture system partially recapitulates the microenvironment of stomach stem cells in the body, and contains all necessary niche factors, including EGF, Noggin, R-spondin, Wnt3A, FGF10, and gastrin (ENRWFG). Specifically, these growth factors supplied in this system act different effects. EGF sustains the continuous self-renewal and proliferation of stem cells and long-term culture   . Key poide novo generation of organoids from directed differentiation of human pluripotent stem cells (PSCs), through manipulation of stem cell niches targeting the FGF, Wnt, BMP, RA (retinoic acid) and EGF pathways  which also exert an important role in stem cell niches, though coculture organoids with other cells type is a feasible and alternative approach. Considering the high cost of cultivation maintenance, it has become more common to culture organoids in medium with niche factors produced by various cell lines than to use commercial products; thus, experimental variation between scientific groups is inevitable.Organoid culture system is a powerful method, but it is important to note its limitation. Current gastric organoids are unable to fully model the H. pylori) infection and gastric cancer, bothers a lot of people in the world. Gastritis is defined as any histologically confirmed inflammation of the gastric mucosa, and its epidemiology overlaps that of H. pylori infection. Longstanding mucosal inflammation leads to the loss of resident gland and the replacement of normal gland by inappropriate glandular unites, which terms as atrophy and metaplasia, respectively. Gastric atrophy and metaplasia are widely recognized as the precursor change for gastric carcinogenesis  is proposed to encompass TFF2 (trefoil factor family 2)-expressing metaplasia, which is linked to mucosal injury associated with parietal and chief cell lose. Recent study documented that during chronic inflammation induced by this bacterium, some chief cells arising from Lrig1+ populations might contribute to SPEM development , leading to disrupted barrier function  seems to lie within the upper neck of the gastric epithelium  based on histological morphology of tumors . Intestiithelium . These a+ gastric stem cells at the base of the antrum in lesser curvature that is a frequent anatomical site for human gastric cancer give rise to all types of epithelial cells. Thus, gastric stem cells in this region might be the potential origin of stomach cancer. Results from a TCGA (The Cancer Genome Atlas) database analysis and immunohistologic staining revealed that intestinal adenocarcinomas of the gastric antrum and gastroesophageal junction were accompanied by the expansion of Lgr5 (Apc (adenomatous polyposis coli) gene in Lgr5-expressing cells leads to macroscopic adenomas and intramucosal well-differentiated carcinoma  failed to initiate tumor growth   disruption or PPARD (peroxisome proliferator-activated receptor delta) overexpression in Villin promoter-expressing stem cells spontaneously result in gastric carcinogenesis  . But, inlineages . Leushaclineages . Besidesogenesis , CCK2R+ gression . More reulations . For gasof cells . Anothere corpus .+ cells may not be the origin cells for pyloric neuroendocrine carcinomas, though this subtype stem cells give rise to endocrine cells in this region  . In gast5– cells . Thus, ocell did . NeverthSince gastric stem cells in adult tissues can regenerate the resident cell types within a lineage, it might be introduced to harness their potential for regeneration of lost or damaged gastric mucosa. As aforementioned above, gastric stem cells can respond to mucosal injury caused by acute damage and chronic inflammation in animal models . But curH. pylori infection, might be one of the mechanisms of oncogenic transformation resulting from this bacterium. Furthermore, disturbance of gastric stem cell pool is involved in the multiple steps of gastric carcinogenesis. In the future, it is clinically significant to uncover the contribution of gastric stem cells to gastric mucosa homeostasis and the development of intestinal metaplasia, dysplasia and final gastric cancer. Further in-depth research is required to reveal the roles of gastric stem cells in stomach diseases and provide new insights for designing strategies to prevent gastric cancer.Gastric stem cells play a key role in the dynamic renewal of gastric mucosal epithelium. Linage tracing approach has made breakthroughs that enable understanding of the physiological characteristics of gastric stem cells in their niches, but further efforts are warranted for defining the various components involved in gastric stem cell niches. Establishment of gastric organoid models overcomes the defects associated with multiple-passaged cells lines derived from cancer specimens, thereby laying a foundation for further in-depth investigations into host-bacterial interactions and gastric carcinogenesis. Hyperproliferation of stomach stem cells, induced by SX researched data for this manuscript, made a substantial contribution to discussion of content designed the figures, and wrote the manuscript. LZ made a substantial contribution to discussion of content, and reviewed and edited the manuscript. Both authors have read and approved the final manuscript submitted.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.