Pinus ponderosa) and dry mixed-conifer forests across a broad geographic range, in part due to relatively high fire tolerance of large grand (Abies grandis) and white fir (Abies concolor). Our results suggest historical forest conditions created by recurrent fire are not readily restored by single fires and landscapes have likely passed thresholds that preclude the effectiveness of managed wildfire alone as a restoration tool.As contemporary wildfire activity intensifies across the western United States, there is increasing recognition that a variety of forest management activities are necessary to restore ecosystem function and reduce wildfire hazard in dry forests. However, the pace and scale of current, active forest management is insufficient to address restoration needs. Managed wildfire and landscape-scale prescribed burns hold potential to achieve broad-scale goals but may not achieve desired outcomes where fire severity is too high or too low. To explore the potential for fire alone to restore dry forests, we developed a novel method to predict the range of fire severities most likely to restore historical forest basal area, density, and species composition in forests across eastern Oregon. First, we developed probabilistic tree mortality models for 24 species based on tree characteristics and remotely sensed fire severity from burned field plots. We applied these estimates to unburned stands in four national forests to predict post-fire conditions using multi-scale modeling in a Monte Carlo framework. We compared these results to historical reconstructions to identify fire severities with the highest restoration potential. Generally, we found basal area and density targets could be achieved by a relatively narrow range of moderate-severity fire (roughly 365–560 RdNBR). However, single fire events did not restore species composition in forests that were historically maintained by frequent, low-severity fire. Restorative fire severity ranges for stand basal area and density were strikingly similar for ponderosa pine ( Wildfire is a foundational disturbance that has shaped ecosystems for millennia, but the impacts of contemporary wildfires in the western United States have become an increasing social, economic, and ecological concern –4. AggreIn the last several years there has been increased effort to identify and address barriers to managed wildfire, large-scale prescribed fire, and cultural burning at broad spatial scales , 21–23. sensu . Es. EsβMCx)We graphically display model estimates for three DBH size classes per species, replicated 75 times for each RdNBR value  to build an output probability of mortality distribution. For models that included an interaction term we simulated estimates for DBH, severity, and the severity × size interaction independently. From the output distribution, we calculated the mean and standard deviation for each size along the range of RdNBR values and plotted these values using locally weighted scatterplot smoothing (LOESS) with first degree polynomial and span of 0.25. We display 10, 20, and 60 cm DBH size classes for conifers, and 10, 20, and 40 cm DBH for hardwoods. For species in which the largest size class was beyond the maximum DBH recorded in the dataset used to generate model estimates, we omit the largest size class. We report results for all 24 species for use in other landscapes or additional inquiry, even though not all were used in stand-level modeling described below.Pinus jeffreyi) to yellow pine and grand fir and white fir to white fir given highly similar ecologies, surveyor difficulties separating the species in the field and known hybridization  fo fo90] foTo assess fire severity ranges with the highest probability of restoring historical basal area and density across national forests and biophysical groups, we calculated the severity range in which ≥ 90%, ≥ 75%, and ≥ 50% of simulated stands fell within the historical range of variation (mean ± 1SD) for each location and forest type. To generalize the restorative fire severity range across all national forests and forest types modeled, we calculated the interquartile range (middle 50%) of severity values that fell within the ≥ 75% restorative range for basal area and density. We graphically display stand-level simulation results colored in relation to the proportion of simulations that fell within the range of variation (mean ± 1SD) of the geographically closest historical reconstruction.https://www.fs.usda.gov/pnw/tools/pnw-fiadb-forest-inventory-and-analysis-database). These plots burned in wildfires across dry forests in Oregon and Washington and were not included in the initial modeling. We selected plots that burned ≤ 15 years prior to measurement and did not display evidence of recent harvest (pre- or post-fire) or other disturbance. Given the limited number of plots that fit our criteria, we retained all plots within ponderosa pine or grand/white fir vegetation zone (Simpson vegetation map classification) [To validate stand-level estimates, we used live tree data from an independent set of 44 one ha plots from the USDA Forest Service Pacific Northwest Research Station Annual Forest Inventory and Analysis program (FIA) PNW-FIA Integrated Database (IDB) (ication) , which w2 ha-1 or density was <5 trees per hectare (TPH) were rounded down to include zero, given the larger plot size (1 ha) used for modeling inherently favored basal area or density estimates very close to but not truly zero at high fire severities. Finally, we assessed the proportion of times our model correctly predicted whether validation stands fell within the ≥ 75% restorative range for basal area or density for the corresponding RdNBR, forest type, and nearest national forest.We used three metrics to assess model performance. First, we assessed average prediction bias using Mean Bias Error calculated as the mean of the differences between observed FIA basal area and density and modeled mean basal area and density for the corresponding measured RdNBR, forest type, and nearest national forest. Next, we compared measured post-fire stand basal area and density for dry mixed conifer and ponderosa pine stands to 95% prediction intervals of our modeled estimates for the corresponding RdNBR, forest type, and nearest national forest. Confidence intervals from our stand-level model with lower bounds where the basal area was < 1 mTo demonstrate mapping restoration probabilities at the landscape scale and potential for this modeling to inform post-fire landscape restoration strategies, we applied our modeled restorative ranges for dry mixed conifer and ponderosa pine stands on the Malheur National Forest to the Parish Cabin fire, which burned 2,727 ha NE of Seneca Oregon in 2012. Pixels were assigned to restoration probability classes based on RdNBR values published in the MTBS database, ILAP Potential Vegetation Types , and modeled restorative fire severity ranges for the Malheur National Forest. To assess post-fire forest composition and structure across severities and between forest types we calculated predicted residual stand basal area by species across tree size classes for several example locations within the Parish Cabin Fire. For this example, we did not filter landscape conditions beyond PVT, but if this method was operationalized, further place-based filtering  may be warranted.Juniperus occidentalis) to 5,668 for Douglas-fir, roughly proportional to their occurrence in fire-prone forests of the Pacific Northwest (Table 2 in 2 = 0.49), ponderosa pine , lodgepole pine , and white fir , which are the focus of our interpretation and use in stand-level modeling. These species account for 95% of individuals modeled in stand-level analyses.Sample size for individual species in our dataset ranged from 94 for western juniper  had a relatively low sample sizes in our dataset , and were a relatively minor component of the tree community in our contemporary modeled plots but are species of ecological importance in many dry forests. In our dataset, western larch was the most fire-tolerant species, displaying strong resistance to low-severity fire and significantly lower mortality with increasing DBH. Given the small sample size for this species, and correspondingly wide confidence interval on effect size estimates there was substantial variation in probability of mortality when western larch was modeled in the Monte-Carlo framework, which propagated into our stand-level modeling . Hardwood tree species, except for big leaf maple (Acer macrophyllum), consistently demonstrated a strong effect of DBH on the probability of mortality and were vulnerable to delayed mortality  occurred as well and this heterogeneity should be not be discounted , 132. EaAlthough there is a growing acceptance of the fundamental role of fire in many ecosystems, post-wildfire assessment and management in the western United States is overwhelmingly focused on negative impacts of wildfire events , 131. ReS1 AppendixSupplemental species- and stand-level model inputs, numerical outputs, and graphical results.(PDF)Click here for additional data file.


Teaching Point: Epipericardial fat torsion is a little-known and uncommon condition with sometimes subtle findings making general awareness essential for detection and for confident diagnosis. Figure 1). Further laboratory blood tests could exclude pulmonary embolism and infectious disease with low D-dimer and absence of systemic inflammation. With this suspicious clinical picture and diaphragmatic tenting, a thoracic computed tomography (CT) without intravenous contrast was requested. The mass-like image on the chest X-ray corresponded to a low density (–80 Hounsfield units) nodular structure with a surrounding soft tissue attenuation rim on the left diaphragmatic dome with a diameter of 2 cm and adjacent lung atelectasis . A clear connection to the mediastinum  was demonstrated, which raised the suspicion of an epipericardial fat torsion. An indication for surgery was retained for definite diagnosis and pain relief. Surgery showed no diaphragmatic defect but revealed a twisted epipericardial fat pad with necrosis adhering to the diaphragmatic side of the left lower lobe . At histology, circumscribed adipose tissue with ischemic necrosis, granulation tissue, hemorrhage, and multinucleated giant cells were seen. The patient had an uneventful recovery and was able to leave the hospital three days later in good general condition.A 21-year-old woman presented to the emergency department with acute left-sided stabbing chest pain with radiation to the left shoulder. The suddenly arising pain was related to inspiration and to supine position but remained absent during expiration. No significant prior medical history or medication intake was noted, and the patient reported no other symptoms. She denied leg swelling or pain, recent flight travel, or smoking. Physical examination and electrocardiogram were unremarkable. A chest radiograph depicted a non-specific left-sided diaphragmatic mass with tenting of the diaphragmatic cupola (This case is an illustration of an atypical localization of an epipericardial fat torsion and necrosis. Clinically epipericardial fat necrosis presents with acute unilateral chest pain, more frequently left-sided, without significant biochemical abnormalities . Imaging


The unprecedented impact of COVID-19 on healthcare professionals has implications for healthcare delivery, including the public health guidance provided to patients. This study aims to assess the response and impact of COVID-19 on chiropractors internationally, and examines the public health response of chiropractors to the COVID-19 pandemic practising under a musculoskeletal spine-care versus subluxation-based care paradigm.A survey was distributed to chiropractors in Australia, Canada, Denmark, Hong Kong, United Kingdom and United States  via professional bodies/publications, and social media. Questions were categorised into three domains: socio-demographic, public health response and business/financial impact. Multivariable logistic regression explored survey items associated with chiropractors practising under different self-reported paradigms.A total of 2061 chiropractors representing four global regions completed the survey. Our recruitment method did not allow the calculation of an accurate response rate. The vast majority initiated COVID-19 infection control changes within their practice setting, including increased disinfecting of treatment equipment (95%), frequent contact areas (94%) and increased hand hygiene (94%). While findings varied by region, most chiropractors (85%) indicated that they had implemented regulator advice on the use of personal protective equipment (PPE). Suspension of face-to-face patient care during the peak of the pandemic was reported by 49% of the participants with 26% implementing telehealth since the pandemic began. Chiropractors practising under a musculoskeletal spine-care paradigm were more likely to implement some/all regulator advice on patient PPE use  and practitioner PPE use ; trust COVID-19 public health information provided by government/World Health Organisation/chiropractic bodies , and initiate patient telehealth in response to COVID-19  compared to those practising under a subluxation-based paradigm.Chiropractors who responded to our survey made substantial infectious control changes in response to COVID-19. However, there was regional variation in the implementation of the advised practitioner and patient use of PPE and limited overall use of telehealth consultations by chiropractors during COVID-19. Musculoskeletal spine-care chiropractors were more adaptive to certain COVID-19 public health changes within their practice setting than subluxation-based chiropractors.The online version contains supplementary material available at 10.1186/s12998-022-00432-6. The unprecedented impact of COVID-19 on healthcare practitioners has been an important focus for public health . This haChiropractors are regulated, primary healthcare professionals who make up a large international workforce  and predDescribe the public health response of practicing chiropractors to COVID-19 within their practice setting;Describe the impacts of the COVID-19 pandemic on the business and finances of practising chiropractors; andTo examine if the public health response to the COVID-19 pandemic of chiropractors self-reporting as practising under a musculoskeletal spine-care paradigm differs from those practicing under a chiropractic subluxation-based care paradigm.To date, very little is known about the impact and response of chiropractors to the COVID-19 pandemic. In response to this gap, we surveyed chiropractors in Australia, Canada, Denmark, Hong Kong, the United Kingdom (UK), and the United States (US) to:Ethical review was approved by the Macquarie University, Faculty of Science and Engineering Human Research Ethics Committee, approval number: 52020679320510. All data were collected, password protected and stored at Macquarie University.An online questionnaire developed by a multidisciplinary research team  was distributed to licensed and practising chiropractors through email communication channels of chiropractic organisations and outlets in Australia , Canada (Canadian Chiropractic Association), Hong Kong (Chiropractic Doctors Association of Hong Kong), Denmark (Danish Chiropractors’ Association), UK  and the US (Dynamic Chiropractic magazine). The questionnaire was distributed  via the LimeSurvey electronic data capture platform. LimeSurvey was used via the university’s official subscription and hosted on secure local infrastructure to ensure the highest standards of privacy, confidentiality and data sovereignty are maintained. Our survey set a browser cookie to ensure participants did not complete the survey more than once. Two reminders to complete the survey were sent during the recruitment period. A link to the online questionnaire was further disseminated widely via Twitter, chiropractic-focused social media groups (Facebook) and email.Key themes and survey questions were developed from other surveys evaluating the response and impact of the COVID-19 pandemic on primary care providers , 6. The The questionnaire comprised three main sections with responses as multiple-choice items or ratings on a 4- or 5-point Likert scale  as appropriate. Pearson’s chi-squared test was used to assess differences between regions in chiropractors’ public health response to and business/financial impacts from COVID-19.t-tests and chi-squared tests for continuous and categorical variables, respectively. Some categorical response items  were dichotomised as “increase” or “no change/decrease” for chi-squared analyses. Only items demonstrating significant between-group differences in the univariate analyses (p < 0.05) were entered into a multivariable logistic regression model. Backward elimination was used to identify items associated with chiropractors practising in a musculoskeletal spine-care paradigm after adjusting for country of practice and age. Statistical significance was set at p < 0.05. Odds ratios were reported with 95% confidence intervals (CI). Statistical analyses were conducted using SPSS Statistics (v27.0) for Windows .Investigation of differences in COVID-19 patient management factors between musculoskeletal spine-care and subluxation-based paradigms was then performed using independent samples In total, 2484 chiropractors participated, with 2061 (83%) fully completing the survey for analysis  and frequent contact areas (94%), increased hand hygiene (94%), increased provision of hand sanitiser for patient use (93%) and increased social distancing of patients within the practice setting (89%) Table .Table 2PResponses varied by country on government/health regulator advice on practitioner use of PPE in response to COVID-19. The overall majority reported that wearing of a cloth or standard surgical mask had been advised (85%), while a smaller percentage (47%) reported that wearing face and/or eye shielding, wearing disposable gloves during treatment (35%), wearing protective clothing (33%) and wearing an N95 respirator/mask (15%) had been advised. Approximately 85% of chiropractors reported that they followed all that had been advised on practitioner use of PPE (when available), while 13% reported they followed some of what had been advised and 2% indicating that they never/rarely implemented recommendations for practitioners use of PPE.Responses also varied by country on government/health regulator advice on chiropractic patient use of PPE in response to COVID-19. The overall majority reported that patient wearing of a cloth or standard surgical mask was advised (82%), while a smaller percentage (9%) reported wearing face and/or eye shielding, wearing an N95 respirator/mask (6%), wearing disposable gloves during treatment (5%) or wearing protective garments/clothing (3%) had been advised. Most chiropractors (76%) reported that they had followed all that had been advised on patient use of PPE (when available) while 8% reported they had followed some of what had been advised and 16% indicating they had never/rarely implemented patient use of PPE recommendations.When participants were asked about the approach to care they would recommend for a patient presenting to their practice with COVID-19 or similar flu-like symptoms, 83% would recommend not providing treatment until the patient has tested negative and after quarantining for at least 2 weeks if testing positive. Approximately 11% recommended these patients not receive treatment until the symptoms had passed, while 4% would proceed with treatment using additional PPE.Only 5% of participants reported using patient telehealth before the pandemic began, while 26% reported telehealth use after the outbreak of COVID-19. Telehealth most often contributed to ≤ 25% of overall patient consultations for those who utilised this modality during the peak of the pandemic. Only 16% reported that a lack of third-party reimbursement was a barrier to their use of telehealth. Participants were divided on whether the public health procedures for manual therapy participants warranted independent guidelines (41% in favour and 46% against) with 13% unsure.Approximately 83% of participants reported providing COVID-19 public health information, such as hand hygiene, social distancing, oral hygiene and face mask wearing to patients during the pandemic  included practitioner sociodemographic background , public health knowledge regarding health regulator COVID-19 advice, public health response to COVID-19, public health views and business impacts Table .Table 6FA core function of healthcare providers is to limit the spread of COVID-19, both within their practice settings and through the promotion of evidence-based public health information. Variations in jurisdictional mandates for infection control will vary between regions, including in response to the ongoing regional changes in pandemic circumstances. This study primarily investigated the COVID-19 public health response of practicing chiropractors broadly  and examined if paradigm predicts awareness and implementation of COVID-19 public health standards. Our study found that a substantial percentage of responding chiropractors, internationally, adopted a range of COVID-19 infection control measures in their practice settings and promoted COVID-19 public health information to their patients, to help reduce disease spread. These activities have the potential to assist wider government efforts to reduce the impacts of the pandemic on society. In addition, our findings show that the COVID-19 pandemic has had a substantial impact on the business and finances of chiropractors.The infection control measures initiated by participants include increased disinfecting of practice areas and treatment equipment, increased personal hand sanitising, provision of patient hand sanitiser and the implementation of patient social distancing. The infection control measures used by respondents were mostly consistent with the information/resources advised by their professional regulatory bodies , 16 and Interestingly, a much lesser percentage of Hong Kong chiropractors who participated reported implementing patient social distancing, changing the spacing of patient bookings and restricting patient care to emergency cases. While professional regulator links to government health directives in Hong Kong had included advice on social distancing  we specuThe majority of participants reported implementing all the advised use of PPE provided by their respective government and/or health regulator. However, this majority was smaller for Australian (59%) and US (70%) chiropractors, which appears to suggest that chiropractors in these countries were more inconsistent in their approach to PPE recommendations despite recommendations made by health authorities –22 and mOur study found that the overall use of telehealth by chiropractors rose to one in four (26%) compared to one in twenty (5%) before the COVID-19 pandemic began. While this increase may be considered substantial for a profession that has traditionally relied on doing things 'by hand', by comparison, a near tenfold uptake of telehealth has been reported within other healthcare professions, such as medicine , 34 and Chiropractors participating in the study were divided on whether the public health procedures for manual therapy practitioners warranted independent guidelines to those needed for other healthcare professionals, as found for dental settings . Future More than 80% of surveyed chiropractors reported providing patients with public health information on COVID-19 infection control measures. This included during routine patient consultations, patient phone calls and through placing COVID-19 brochures and posters within their practice environment. The provision of reliable and accurate public health information by trusted healthcare professionals can improve patient protection from COVID-19 infection  and reduOur study substantiated that the COVID-19 pandemic has had considerable negative impacts on the business and finances of chiropractors, which concurs with findings reported for other healthcare professions , 6. OverThe practice paradigm study variable as operationalized in our survey did not allow the option for participants to self-select identifying with both paradigms in more equal measure, although chiropractors can practice under both paradigms as has been reported in other studies –63. For Musculoskeletal spine-care chiropractors were also more likely to trust COVID-19 public health information provided by government, public health authorities and professional associations/boards—information sources with key responsibilities toward disseminating COVID-19 information based on current scientific consensus. This finding may also help to explain why musculoskeletal spine-care chiropractors are more likely to be aware of and implement certain COVID-19 infection control measures when compared to subluxation-based practitioners. It is vital that all chiropractors remain up to date with the advice provided by recognised health authorities to protect themselves and the public they serve during infectious disease outbreaks.While our study identified that subluxation-based chiropractors constitute a smaller percentage of practitioners, more research is needed to understand how self-report practice paradigms may influence the public health knowledge and behaviours of chiropractors. Findings from this research may assist any knowledge translation strategies or infection control training for chiropractors if necessary to reduce the risk of communicable disease transmission, such as COVID-19, within chiropractic settings .The study is the first chiropractic COVID-19 study to be conducted across several international regions. However, this study has several limitations. Self-reported data collection is subject to recall bias which may be further influenced by the timing of the survey relative to the previous peaks COVID-19 spread in the different countries. Those who self-selected to participate in the study may be different to non-participants and there is a risk of social desirability bias in the answers provided by those who did participate. The generalizability of the study is unknown because it was not possible to report the survey response rate accurately with an unknown number of chiropractors who viewed the survey preventing a precise assessment and acknowledge that the raw data should not be assumed to be representative of the greater population. This includes how often the survey was shared via social media connections and through personal emails and because the survey was not shared as a single email message, but most often embedded within another email within other online pages of information by chiropractic associations and professional online magazine. The reasons for why some chiropractors choose to participate and others did not, and the reasons for why some participants only partially completed the survey is unknown , 68. TheFurther, representativeness of the sample is unknown because there was no reliable demographic information for chiropractors in most countries surveyed, hence non-response bias was unable to be measured. Response bias may exist because the survey dissemination was limited to those with email and internet access and to members of the professional associations and subscribers of the professional magazine utilised for the survey distribution and the unequal representation of participants across geographical regions and regulatory frameworks. Aside from face validity, items in this survey have not been assessed for their property measurements, including the question used for the identification of practice paradigm, which was limited to only three options i.e., those more closely musculoskeletal or subluxation-based, or neither. This leaves the possibility of additional paradigm subgroups to exist that are not accounted for in this study, such as chiropractors who practice more equally under both paradigms. This lack of choice may have impacted our response rate and representativeness of our survey since our respondents may not sufficiently represent the true self-identity professed by some practitioners within the general chiropractic population, as reported in other studies –63. TherDue to likely selection bias of our sample, we do not have confidence that these results are representative of the wider chiropractic population. Chiropractors in Australia, Canada, Denmark, Hong Kong, the UK and the US who participated in the study initiated a range of COVID-19 infectious control measures within their practice settings and have been providing patients with COVID-19 public health information. However, the implementation of telehealth and use of PPE was less uniform, warranting further research. Similar to other healthcare providers, COVID-19 has had a substantial negative business and financial impacts upon chiropractors. Finally, chiropractors who practice under a musculoskeletal spine-care paradigm were more likely to have knowledge of and implement several COVID-19 public health infection control measures important to reducing disease transmission compared to chiropractors practicing under a subluxation-based paradigm. It is vital that all healthcare providers implement and promote evidence-based public health behaviours to reduce the spread of COVID-19.Additional file 1. Practitioner survey questionnaire.


To evaluate the mechanisms attributed to the prognostic value of peripheralischemic microvascular reserve in patients with sepsis.This observational cohort study enrolled 46 consecutive septic patients inthe intensive care unit between November 2020 and October 2021. After fluidresuscitation, the peripheral ischemic microvascular reserve was evaluatedusing the association of postocclusion reactive hyperemia with theperipheral perfusion index. Additionally, peripheral venous blood sampleswere used to evaluate the neuropeptide calcitonin gene-related peptide andsubstance P levels in the upper limb before and immediately afterpostocclusion reactive hyperemiaThere was no statistically significant correlation (p > 0.05) betweenbasal values (pg/mL) or variations from neuropeptide levels (%) and theperipheral ischemic microvascular reserve (%).Although calcitonin gene-related peptide and substance P may have aprognostic role in sepsis, these neuropeptides do not appear to contributeto peripheral ischemic microvascular reserve. Even thoughthere have been scientific advances in its pathophysiological understanding andmanagement, this syndrome affects millions of patients annually and remains acritical condition associated with high mortality rates and short- and long-termmorbidity.Sepsis is characterized by a widespread and deregulated immune-metabolic hostresponse induced by an infection that results in potentially fatal organdysfunction. Therefore, safe and validated methods to assess vascularreactivity at the bedside are sought in sepsis. Recent findings demonstrated thesafety and robust prognostic value of combining the noninvasive methods peripheralperfusion index (PPI) and postocclusive reactive hyperemia test (PORH) to evaluatethe percent change of blood flow in response to flow-dependent tissuehypoxia.,5 Thus, the combined PORH/PPI could estimate themicrovascular reactivity and reserve of the examined tissue in septic shock.Under pathological conditions of sepsis, persistent microcirculatory disorders, suchas arteriolar hyporesponsiveness, and capillary dysfunctions have been associatedwith organ dysfunction and the worst prognosis. However, there is no clear evidencein the literature to elucidate this unexpected finding related to PIMR or itspotential prognostic role. A possible hypothesis is based on the role of the sensoryneuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP). Theseneuropeptides constitute part of the mechanisms responsible for cutaneousvasoregulation andimmune modulation and haveprognostic value in sepsis.-9 Furthermore, experimental evidencestrongly suggests sensory nerve involvement in the cutaneous postischemic responsein healthy conditions.,11 Thus, we hypothesized that theelevation of neuropeptides after the POHR/PPI test could contribute to the highmicrovascular reserve in more severely ill patients and concomitantly indicate amore significant immune dysregulation in these patients. Hence, to answer thisquestion, the present research investigated a subgroup of a validation study ofPOHR/PPI as a method of microvascular evaluation of septic patients.Interestingly, a paradoxical observation was made when using PORH/PPI as ameasurement method for patients with septic shock: those with higher peripheralischemic microvascular reserve (PIMR) had a worse prognosis.Complexo Hospitalar de Clínicas of theUniversidade Federal do Paraná (CHC-UFPR), protocol4.754.428/2020.This observational cohort study was conducted in the 15-bed Brazilian intensivecare unit (ICU) between November 2020 and October 2021. All survivorparticipants or their legal representatives provided written informed consent,except in the case of the patient’s death, in which case the written informedconsent was waived. The research was approved by The Human Research EthicsCommittee of the 3, the international normalized ratio - RNI > 2.0, oractivated partial thromboplastin time - aPTT > 70 s), the presence of severeactive bleeding, infective endocarditis, inaccessible perfusion assessment,and refusal of the patient to participate in the study.Consecutive adult patients (18 years or older) with a diagnosis of sepsisadmitted to the ICU or within 24 hours after its onset in patients previouslyadmitted for other causes were considered eligible for inclusion in the study.The exclusion criteria to minimize potential confounding factors or risks ofpossible hemorrhagic and ischemic complications of procedures were pregnancy,severe hepatopathy (Child-Pugh class C), severe coagulopathy  above 65mmHg.According to the current consensus on sepsis (2016), this syndrome is identifiedas the presence of an infection associated with an acute change in theSequential Organ Failure Assessment (SOFA) score of two points ormore. Themanagement started as soon as sepsis was detectable. First, if there was a highlikelihood of this syndrome, antimicrobials were administered within the firsthour of recognition after collecting blood and suspicious focus culture. Second,in cases of signs of hypoperfusion or septic shock, 30mL/kg of balancedcrystalloid fluids was administered at the discretion of the patients’physicians over the first 3 hours of sepsis diagnosis. Additionally, accordingto the criteria of the physician, if there was an individual clinicalindication, resuscitation was continued until there was a lack of reaction topassive-leg raising  or no respiratory variance of inferior venacava diameter (the cutoff of 18%). If MAP persisted less than 65mmHg,norepinephrine was used to obtain MAP ≥ 65mmHg. Vasopressin was the drugof choice for association with noradrenaline in refractory cases. Thehemodynamic goals were MAP ≥ 65mmHg, urine output > 0.5mL/kg/h andcentral venous oxygen saturation (ScvO2) > 70%.All selected patients were conducted following a local institution’srecommendations adapted from the Surviving Sepsis Campaignguidelines.The assessment of septic patients occurred within 24 h after proper hemodynamicresuscitation, which was established by stable macrohemodynamics at the end ofthis period. The data collected during the study included demographiccharacteristics, medical history, infection source and comorbidities, SOFAscores, and Acute Physiology Chronic Health Evolution II (APACHE II) scores. Inaddition, all hemodynamic parameters (if available), neuropeptide levels, andperipheral variables were measured between 6 and 24 hours of sepsis diagnosis.In addition, intensivists were blinded to peripheral ischemic microvascularreserve variables to avoid possible treatment interference. Finally, thepatients were followed for 28 days of sepsis diagnosis or hospital release. Its value represents anindicator of peripheral vasomotor tone and peripheral perfusion. This variable was measuredafter proper hemodynamic resuscitation by attaching a pulse oximeter probe. First, after signal stabilization, the PPI valueswere recorded every 30 seconds for 5 minutes, and the average of the values wascalculated to determine the PPI basal value. Subsequently, a test of themicrovascular reactivity, called the PORH test, was performed: the cuff of a sphygmomanometerwas inflated around the homolateral upper limb at 50mmHg above systolic pressurefor 3 minutes. After deflation of the sphygmomanometer cuff, PPI values wererecorded every 30 seconds for 5 minutes, and the higher value corresponded tothe PPI peak value. Reactive hyperemia was established by changes in blood flowverified using PPI values. Finally, the estimation of the maximum change inblood flow in response to tissue hypoxia  was established by the ∆ PPI peak (%), which was calculated using thefollowing formula:Peripheral ischemic microvascular reserve was assessed using a combination of thePPI and PORH tests. The PPI corresponds to a parameter derived from thephotoelectric plethysmography signal of a pulse oximeter, calculated as thepulsatile blood flow ratio  to nonpulsatile blood flow  nail bed from the emission of twosources with two different wavelengths (660 and 940nm).Universidade Guarulhos, SP, in refrigerated boxescontaining dry ice.Venous blood samples were collected within the first 24 hours of sepsis diagnosisafter appropriate hemodynamic resuscitation to determine serum concentrations ofthe neuropeptides CGRP and SP. Approximately 5mL of venous blood was collectedfrom the upper limb evaluated in the forearm region before and immediately afterthe PORH test. These samples were deposited into test tubes containingethylenediaminetetraacetic acid (EDTA) and subsequently centrifuged at 1200relative centrifugal force (RCF) at 4°C for 10 minutes. Approximately 1mL ofplasma was frozen at -80°C. The samples were transported between CHC-UFPR -Curitiba, PR, to the Laboratory of Inflammation and Immunology atThe presence of the neuropeptides SP and CGRP in human blood samples was measuredby ELISA. Substance P and CGRP were quantified using the Substance P ParameterAssay Kit  and Human CalcitoninGene-Related Peptide ELISA Kit  according tothe manufacturer’s instructions. A competitive binding ELISA was used todetermine the SP concentration. Briefly, 50µL of the samples were addedto 96-well plates and incubated with monoclonal antibodies for SP and conjugatedto horseradish peroxidase. The plates were incubated for 3 hours, allowing thebinding between the monoclonal antibody and the goat anti-mouse antibody coatedonto the microplate. Subsequently, the plates were washed, and the substratesolution was added to the wells to determine the bound enzyme activity. Theabsorbance measurement was established in a microplate reader set at 405nmwavelength with wavelength correction set at 570nm. The SP concentration wasexpressed in pg/mL.Calcitonin gene-related peptide analyses were performed using the double antibodysandwich technique. Briefly, 100µL of the samples were added to 96-wellplates and incubated with CGRP monoclonal antibody for 90 min. Next, the plateswere washed, and 100µL of biotinylated CGRP antibody was added to eachwell. Finally, the plates were incubated for 60 minutes. Subsequently,avidin-peroxidase was added, and the absorbance was measured in a microplatereader set at 450nm (630nm wavelength correction). The CGRP concentration in thesamples was expressed in pg/mL, established by a correlation between theabsorbance data and the calibration curve.The variation in neuropeptide levels in response to tissue hypoxia wasestablished using the following formulas:The ambient bedside temperature was controlled at 22ºC. The medical procedure wasmade in a supine decubitus and performed in the upper limb without anintra-arterial catheter for MAP measurement.The primary outcome was the correlation between the peripheral ischemicmicrovascular reserve  and variation in the neuropeptide CGRP andSP levels  from the first day of sepsis diagnosisafter fluid resuscitation. The secondary outcomes included the correlationbetween basal venous neuropeptide CGRP and SP levels and the PPI basal values,the correlation between basal venous neuropeptide CGRP and SP and the peripheralischemic microvascular reserve , and the correlation betweenbasal venous neuropeptide CGRP and SP and lactate levels within 24 h of sepsisdiagnosis after fluid resuscitation.The Shapiro-Wilk test was utilized to determine the normality of the sample.Parametric data are represented as the means ± standard deviation, whilethe medians and interquartile range (IQR) were used for nonparametric data.Percentages represent proportions. Correlation tests between the continuousvariables of ∆ PPI peak (%) and ∆ neuropeptide levels (%), between venousneuropeptides CGRP and SP lactate levels pre-PORH and the PPI basal values, andbetween venous neuropeptides CGRP and SP lactate levels pre-PORH and theperipheral ischemic microvascular reserve  were performed usingthe Spearman test. The Wilcoxon signed-rank test compared neuropeptide levelsbetween the first and second measurements. The significance of the results wasdetermined by a p value < 0.05. All reported p values are two-sided. IBMStatistical Package for the Social Science (SPSS) 23 and GraphPad Prism 6programs were used for all analyses. giving an overall sample of 46 patients. Thealpha error chosen was 0.05, and the p values were corrected for multiplecomparisons.The calculation of sample size was established based on the pilot study. Weestimated a sample size of 38 patients to find at least a moderate correlation(r = 0.5), with a sample power of 90%. Because the neuropeptide levels arenonparametric variables, an addition of 15% was made,This research followed the STROBE guidelines for reporting results.Forty-six patients were included during the study period after proper fluidresuscitation and had subsequent peripheral ischemic microvascular reserveevaluation associated with the analyses of pre- and postischemic SP and CGRP levels. The cliAs shown in The present study also sought to evaluate a possible association between basalneuropeptide levels and peripheral perfusion but observed no significant correlationbetween the basal PPI and basal levels of the neuropeptides CGRP (p = 0.95) and SP(p = 0.82). Finally, we found no correlation between lactate level, an acceptedmarker of tissue hypoperfusion, and the basal neuropeptides CGRP (p= 0.66) and SP (p= 0.92). Contrary tothe behavior of other microvascular territories, a better fingertip ischemicmicrovascular reserve was associated with higher mortality, thus suggesting afunctional rather than a structural mechanism. Nevertheless, no clear evidence has elucidated theparadoxical finding involved in the high PIMR or its potential prognostic role.Current evidence has demonstrated the ability of peripheral ischemic microvascularreserve measurements to predict the 28-day mortality rate in septic shockpatients. the inhibition of these substances does not appear tointerfere with reactive hyperemia in the skin.,20 Concerning thephysiological mechanisms involved in skin microvascular reactivity, evidence hasshown that the expression and release of neuropeptides via sensory nerve fibers andsubstances derived from cytochrome epoxygenases appear to play an essential role inthe peak and timing of hyperemia in healthy individuals.,22Moreover, in addition to its performance in cutaneous vasoregulation, robust evidence has demonstratedits value in predicting sepsis mortality.-9The skin corresponds to one of the most accessible organs in the human body, allowingclinicians to evaluate cutaneous microvascular reactivity with noninvasive bedsideparameters, such as the PPI associated with the PORH test. Although some mechanisms,such as the roles of nitric oxide (NO) and prostacyclin (PGI-2), seem to be crucialto vasomotor dysfunction in sepsis, andcan simultaneously be released after the occlusion test, theoretically explaining the functional mechanismlinking a high reserve and higher mortality. In this way, a microhemodynamic testcould theoretically be used to indicate a phenotype of more severe septic patients,likely due to more significant immune dysregulation. Unfortunately, our findings didnot corroborate this hypothesis. Contrary to expectations, posttest plasma CGRPlevels remained similar to pretest levels. Additionally, SP levels were reducedafter the test. However, it is well known that several enzymes, including neutralendopeptidase, dipeptidyl aminopeptide IV, and angiotensin-converting enzyme,degrade SP. Therefore, some ofthese peptidases may have increased activity during the hypoxic-ischemic stimulus ofthe test in septic patients. In this sense, other studies are needed to confirm thisstatement.The motivation of this study was to investigate the role of the neuropeptides SP andCGRP in the ischemic skin response of septic patients. These neuropeptides have animmune-modulating function Thus, thecomparison of maximum response peaks may not fit the hypothesis. Third, themeasurement of neuropeptides via venous blood may not represent the measurementevaluated in capillaries. However, our study used an intraindividual comparativeanalysis, which reduced the possible influence of the mentioned collection sites.Finally, in this study, the evaluation of ischemic peripheral microvascular reserveassociated with the dosage of neuropeptides in septic patients was not compared withhealthy patients, thus limiting the conclusions.However, some limitations should be considered before completely ruling out thispossibility. First, the time of assessment and measurement was not ideal, sincethese mediators could have been released later. Second, it was impossible to obtaindifferent dosages of neuropeptides over time to assess a response curve compared tothe reserve curve. This limitation is corroborated by one of the interventionalstudies, which, through the infusion of these neuropeptides into the skin bymicrodialysis in healthy subjects, observed potent and lasting vasodilation in thecase of CGRP and a milder and short duration associated with plasma leakage forSP.In conclusion, although calcitonin gene-related peptide and substance P may have aprognostic role in sepsis, these neuropeptides do not appear to contribute toperipheral ischemic microvascular reserve.


COVID-19 was the third leading cause of death in the United States in 2020. Prior to the wide dissemination of SARS-CoV-2 vaccines, individual prevention behaviors, such as wearing face masks, have been the primary non-pharmaceutical interventions to reduce infections. We surveyed 404 North Carolina residents recruited through Amazon MTurk in July 2020 to assess adherence to key prevention behaviors  and barriers to and facilitators of adherence. Participants reported past 7-day prevention behaviors and behavioral barriers and facilitators informed by the Integrated Behavior Model and the Health Belief Model . Reported adherence to each behavior in the past 7 days was generally high, with lower adherence to 6-foot distancing and mask wearing in the work context. The most commonly endorsed barriers to 6-foot distancing included physical impediments, forgetting, and unfavorable descriptive norms. For mask wearing, ability to keep a distance, discomfort/inconvenience, and forgetting were most commonly endorsed. In logistic regression models, injunctive social norms followed by perceived personal agency were the strongest independent correlates of 6-foot distancing. Behavioral attitudes and injunctive social norms were independently associated with mask wearing. For gathering size limit adherence, perceived personal agency was the strongest independent predictor followed by perceived severity of COVID-19. Messaging campaigns targeting these barriers and facilitators should be tested. Interventions improving the convenience and salience of physical distancing and mask wearing in high-density public places and places of work may also promote prevention behaviors. COVID-19 was the third leading cause of mortality in the United States in 2020 with an estimated 375,000 deaths attributed to the disease . Like thBefore the arrival of an effective, approved, and broadly disseminated vaccine for COVID, behavioral prevention strategies were key non-pharmaceutical interventions (NPIs) before vaccines were given Emergency Use Authorization in December 2020 . Even wiDespite guidelines and mandates for these key COVID-19 prevention behaviors  and the devastating impact of the pandemic, media reports and escalating case numbers suggested that adherence to these recommended behaviors was mixed . DespiteTo improve efforts to control the COVID-19 pandemic in North Carolina and the United States, we need to understand what modifiable barriers and facilitators will help increase COVID-19 prevention behaviors at the population level. To this end, we conducted a survey of North Carolina residents to describe adherence to COVID-19 prevention behaviors, and to assess intra- and interpersonal factors associated with adherence including self-reported barriers to these behaviors. The results of this study highlight targetable barriers to and facilitators of behavior change communication and interventions which may further our efforts to control the COVID-19 pandemic and future respiratory infectious disease epidemics.In March 2020, an interdisciplinary research team was assembled to assist the NC DHHS in developing messaging to promote COVID-19 prevention behaviors. To inform the development of these messages, we conducted a series of online surveys of North Carolina residents recruited via Amazon Mechanical Turk (MTurk). Our agile process for message development and testing has been previously described . The datIn all, 404 North Carolina residents were recruited on a convenience basis to participate in an anonymous survey via Amazon MTurk and self-administered the survey online using the Qualtrics platform. To be eligible to participate, individuals had to report being a current North Carolina resident and at least 18 years old. The target sample size of approximately 400 participants was chosen because of the feasibility of recruitment within our study budget and time frame (this was part of a rapid data collection effort in support with the NC DHHS’ development of COVID-prevention messaging ).Participants reported their age, race and ethnicity, household income, education, residence setting , current work status, and political affiliation. They also reported whether they had had a positive COVID-19 test or otherwise suspected that they had had a COVID-19 infection but had no confirmatory test.6-foot distancing, participants reported how much of the time they kept a distance of 6 feet or more from non-household members in three contexts: at work (if applicable), in an indoor setting away from home, and in an outdoor setting away from home. For mask wearing, participants reported how much of the time they wore a covering over their mouth and nose in three contexts: at work (if applicable), in public settings where they were able to keep a 6-foot distance from others, and in public settings where they were unable to keep a 6-foot distance from others. Participants rated each item on a 4-point scale . We categorized responses of “most” or “all of the time” as adherent for each behavior in each relevant context. We also asked participants about their attendance of social gatherings with non-household members, asking them to report the size of the indoor and outdoor gatherings they had attended, if any. We categorized participants as being adherent with avoiding “large” social gatherings if they attended no gatherings exceeding the limits set by state executive orders at the time the survey was administered (10 for indoor and 25 for outdoor).Participants were asked to self-report three key COVID-19 prevention behaviors in the past 7 days. For Participants who reported not adhering to 6-foot distancing and mask wearing “all of the time” in each of the relevant contexts were asked to report barriers to each behavior through a multiple-choice question . They also rated the perceived severity of being infected with COVID-19, based on either their own experience of infection or anticipated severity among those not reporting a known or suspected infection .We also measured six cognitive and normative constructs that we hypothesized would promote COVID-19 prevention behaviors, informed by the Integrated Behavior Model and the Health Belief Model : perceivBehavioral attitude statements reflected the perceived importance of each prevention behavior . Injunctive norm statements addressed the perceived approval for each behavior in participants’ social circles . Descriptive norm statements pertained to perceived local adherence levels with each behavior . Finally, personal agency statements reflected the perceived ease of performing each behavior (“It is easy to [keep a distance of 6 feet or more from others in public spaces/wear a face mask when I am in public/avoid large gatherings]”).For each COVID-19 prevention behavior, participants rated their agreement with statements regarding their attitude toward the behavior, perceived social norms for the behavior, and their personal agency over the behavior, rated on a 5-point Likert-type scale. All study procedures were approved by the institutional review board of the University of North Carolina at Chapel Hill (IRB #20-0995). All participants completed electronic informed consent prior to completing the survey.Analyses were completed in SAS v 9.4. We first generated statistics describing the sociodemographic composition of the sample, adherence to the three COVID-19 prevention behaviors of interest, and reported barriers to and hypothesized facilitators of each behavior . We then assessed the hypotheses that North Carolina residents reporting higher/more positive levels of each facilitator would be more likely to adhere to each prevention behavior than those reporting lower/less positive levels of each facilitator . Convenience issues were also common; 31% reported “It is uncomfortable or inconvenient to wear a mask” and 29% reported “I forget to bring/wear a mask.” Efficacy doubts were also reported by 20% of participants (“I doubt wearing a mask will protect me or others from the coronavirus”) and 19% reported not wearing a mask because “I’m not sick/I don’t have COVID-19 symptoms.” Norm-related barriers were also reported by some participants: 17% said they did not always wear a mask because “most people are not wearing masks” and 14% were “concerned what others will think of me or do to me if I wear a mask.” All other responses were endorsed by fewer than 14% of participants.Among the 372 participants who had not had a positive SARS-CoV-2 test, 47% believed they had a small chance of being infected in the next year while 39% believed they had a medium chance . When asParticipants reported highly positive attitudes toward the importance of 6-foot distancing (88% agree or strongly agree), and moderately positive injunctive social norms (77% agree or strongly agree) and perceived personal agency (62% agree or strongly agree) for distancing. Lowest rated was descriptive social norms, with only 55% of participants agreeing or strongly agreeing that most people they see maintain a 6-foot distance from others in public.Regarding mask wearing, participants reported highly positive attitudes toward mask wearing (87% agree or strongly agree) and high perceived personal agency for mask wearing (86% agree or strongly agree). Respondents reported moderately positive injunctive social norms toward mask wearing (76% agree or strongly agree), but less positive descriptive social norms for mask wearing (65% agree or strongly agree).For social gatherings, participants reported highly positive attitudes toward avoiding large social gatherings (89% agree or strongly agree) and high perceived personal agency for avoiding large gatherings (86% agree or strongly agree). Respondents also reported moderately positive injunctive social norms (78% agree or strongly agree) and descriptive social norms (77% agree or strongly agree) for avoiding large social gatherings.In bivariate analyses, all hypothesized predictors were associated with reported adherence to 6-foot distancing except descriptive social norms . Most clAll hypothesized predictors were associated with adherence to mask wearing most or all of the time in bivariate analyses . A higheIn contrast, only three of the hypothesized facilitators were associated with avoidance of large social gatherings in bivariate analyses. Most strongly associated with odds of adherence was behavioral attitudes . Greater perceived severity of COVID-19 infection  and perceived personal agency  were moderately associated with avoiding large social gatherings. In adjusted analyses, only perceived severity  and perceived personal agency  remained associated with avoiding large social gatherings.A majority of participants reported adhering to each COVID-19 prevention behavior, while 18% to 30% of respondents did not regularly adhere. While reported 6-foot physical distancing was lowest in the work context (yet still high with 70% adherence), public health and workplace safety agencies recommend mask wearing in work contexts where physical distancing is not possible , providiReported mask-wearing adherence was high overall but was also lowest in the work context, and highest in situations where participants were unable to maintain physical distancing. While these trends are aligned with recommendations, 15% of participants did not report wearing a mask most or all of the time where physical distancing was not possible. The most common self-reported barriers to mask wearing endorsed by participants included convenience or comfort issues, unfavorable social norms, efficacy doubts, and a belief that masks are only needed for people who feel sick or have COVID-19 symptoms. The latter two barriers may be related to initial miscommunication at the federal and local level regarding the importance of mask wearing among asymptomatic individuals , althougWhile most participants were adherent with state social gathering size limits at the time of data collection, a sizable minority—one quarter—reported nonadherence. Moreover, simple adherence to gathering size mandates may not be sufficient at a population level to minimize transmission , and morThe results of this study should be interpreted with key limitations in mind. First, participants were recruited using convenience sampling through MTurk and may not be representative of the population of North Carolina. Importantly, certain demographic categories including Black residents of North Carolina are noted to be underrepresented in the sample. Second, reported adherence to and attitudes toward COVID-19 prevention behaviors are likely susceptible to social desirability bias. However, this potential bias is mitigated by the fact that participants completed the survey anonymously and prompts were included to acknowledge the difficulty of perfect adherence . Third, reported adherence to each behavior is also likely susceptible to recall bias. To minimize this issue, we restricted the recall period to the past 7 days. Finally, given the cross-sectional nature of the data, causal inferences for the associations observed should be drawn with caution. Adherence to prevention behaviors reported cross-sectionally may also not reflect the level of adherence at the time of publication. Understanding of the primary barriers and facilitators associated with preventive behaviors nevertheless provides actionable and durable evidence to inform communication, programs, and structural interventions to reduce infections in this pandemic and future pandemics involving other coronaviruses and similar respiratory infectious diseases.Adherence to COVID-19 prevention behaviors was generally high among North Carolina residents surveyed in July 2020. Yet approximately one fifth to one quarter of participants were nonadherent with each protective behavior, with high levels of reported large indoor gatherings presenting a particular area of concern. Barriers reported by participants, as well as results of our models examining hypothesized facilitators of these prevention behaviors, suggest that future messaging campaigns should target efficacy beliefs for prevention behaviors, social norms, and perceived severity of COVID-19 infection. Interventions improving the convenience and salience of physical distancing and mask wearing in high-density public places  may also combat key barriers to these behaviors. Future assessments are needed to better understand evolving COVID-19 prevention behaviors, attitudes, and norms.


Stem cells (SCs) have evolved as an interesting and viable factor in ophthalmologic patient care in the past decades. SCs have been classified as either embryonic, mesenchymal, tissue-specific, or induced pluripotent cells. Multiple novel management techniques and clinical trials have been established to date. While available publications are predominantly animal-model-based, significant material is derived from human studies and case-selected scenarios. This possibility of explanting cells from viable tissue to regenerate/repair damaged tissue points to an exciting future of therapeutic options in all fields of medicine, and ophthalmology is surely not left out. Adipose tissue obtained from lipo-aspirates has been shown to produce mesenchymal SCs that are potentially useful in different body parts, including the oculo-visual system. An overview of the anatomy, physiology, and extraction process for adipose-tissue-derived stem cells (ADSC) is important for better understanding the potential therapeutic benefits. This review examines published data on ADSCs in immune-modulatory, therapeutic, and regenerative treatments. We also look at the future of ADSC applications for ophthalmic patient care. The adverse effects of this relatively novel therapy are also discussed. Adipose-tissue-derived stem cells (ADSCs) are mesenchymal cells derived from adipocytes, as the name implies . The proVarious cellular components make up the SVF . These iAdipose tissue exists in various isoforms that chiefly differ in their thermogenic capacities. These include brown adipose tissue  and whitSCs can be seen as undifferentiated, unspecialized cells possessing characteristics that allow them to proliferate and integrate into differentiated cells under prime physiological conditions . The vasTotipotent stem cells (TSCs) can differentiate into all tissues present in the entire living organism, which includes both embryonic and extraembryonic constituents . EmbryolPSCs can differentiate into the three germ layers but cannot proliferate to extraembryonic elements (placenta) , which iFrom PSCs, multipotent, oligopotent, and unipotent SCs emerge down the differentiation lineage. Multipotent SCs possess characteristics to differentiate into cells originating from specific lineages . HematopAdult or somatic stem cells (SSCs) exist as unspecialized, undifferentiated cells in the midst of other differentiated cells . These cMSCs differentiate into several tissues of a multicellular lineage. These cells possess broader multipotent characteristics (via iPSCs) when compared to other types of SSCs . MSCs haStem cell/regenerative medicine has been developed from the discovery that SCs can be modulated accordingly for the potential enhancement of variable tissue repair and regeneration . NumerouIn stem cell research, MSCs are commonly derived from autologous, allogeneic, and xenogeneic sources . ExperimThe effects of adipose-derived MSCs (ADSCs) on multiple acquired and degenerative disorders have been investigated in numerous animal-based research studies but sparingly in human trials. Theoretically, ADSCs have been found to have therapeutic significance around the site of delivery via immunosuppressive , angiogeThe extracellular vesicles of adipose tissue have been hypothetically viewed as secretomes for the potential development of “cell-free” regenerative therapies. The future discovery of alternative cell-free strategies could help ease ethical concerns limiting the unrestricted practice of SC medicine in modern times.Adipose tissue can be extracted during elective surgery with little to no risk to the donor. It is also possible to extract adipose tissue using a fine-needle aspiration technique. The extracted adipose tissue is easily cryopreserved for extended periods with minimal loss in viability . ADSCs aFurther studies have assessed the viability of adipose stem cells derived from fat harvested via either tissue resection or power-assisted liposuction . Cell viRecords that focused on the use of adipose stem cell tissue in ophthalmology;Studies on the use of stem cells in human tissue;Full-text papers;Journal articles published within the last 10 years, ranging from 2012 to 2022;Studies published in the English language;Primary sources with qualitative or quantitative research designs.Animal and animal-tissue-based studies;Studies that focused on other fields of medicine outside ophthalmology;Studies not published in English;Journal articles published outside the range from 2012 to 2022To ensure the accuracy and transparency of the records used for this study, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)  was usedIn the PRISMA chart, i is the total number of records identified through the PubMed search (150); ii is the net number of articles identified after removing duplicates (147); iii is the number of articles that passed the screening criteria to be included in this review (147); iv is the number of records that did not meet the screening criteria (37); v is the number of full-text articles among the records that met the screening criteria (110); vi is the number of articles further excluded with reasons (41); and vii is the final number of articles used in this review (69).The following describes the PubMed search criteria for ADSCs in ophthalmology. The inclusion criteria limited articles to publications involving the use of adipose-tissue-derived stem cells in an ophthalmology setting. The earliest year of publication of the articles was set to be a maximum of 10 years before writing this paper (2012). Only articles that were available for free and as full texts were included. One article was removed because it was published in a language the authors could not read. PubMed keywords were “Adipose-derived” AND “stem cells” OR “stem” AND “cells” OR “stem cells” AND “ophthalmologie” OR “ophthalmology” OR “ophthalmology” OR “ophthalmology”.The search strategy was “Adipose-derived”[All Fields] AND (“stem cells”[MeSH Terms] OR (“stem”[All Fields] AND “cells”[All Fields]) OR “stem cells”[All Fields]) AND .A review of specific uses of ADSCs in ophthalmology suggests that the ocular structure of interest is a determinant for the optimal selection of delivery protocols. Numerous studies in the literature in this field have shown the possibilities of ADSC therapy to treat various types of ocular surface diseases (OSDs), including chemical burns, corneal epitheliopathy, corneal laceration, dry eye disease, limbal stem cell deficiency, keratoconus, etc. .The cornea is a trilaminar structure. The epithelial layer is derived from the surface ectoderm; the stroma is from neural crest mesenchyme; and the endothelial layer is from neural crest cells. Considering the multicellular differentiation potential of corneal cells, the adoption of ADSCs in corneal treatment could hypothetically improve the availability of viable lamellar tissue . ADSC-coEspandar et al. grafted xenogeneic hADSCs onto acutely afflicted rabbit corneas using a scleral contact lens carrier. The study showed a reduction in ocular inflammatory signs that were not observed in controls . A similCorneal neovascularization readily occurs when there is an insult to the corneal integrity . EpithelOphthalmic surgery is often necessary for the management of ocular morbidity. Surgery can offer therapeutic benefits; however, ocular complications such as trauma must be considered due to specific procedures, inflammation, and infection. Penetrating keratoplasty and keratoprosthesis are invasive treatment options for visual impairment due to extensive corneal scarring. The use of donor corneas has numerous limitations, which include a lack of donor tissue, the possible rejection of donor tissue, high complication rates, elevated risks of postoperative complications, increased induced astigmatism, etc. .Less invasive options are becoming of increasing interest in the field regarding corneal repair. Studies have shown that exosomal microRNA-19 suppresses the differentiation of corneal stromal keratocytes into myofibroblasts . Ma et aADSC therapy has been shown to enhance surgical outcomes and reduce postoperative complications. El Zarif et al. reviewed the laser-assisted intrastromal implantation (via injection) of autologous adipose-derived stem cells in patients with advanced keratoconus to aid in corneal stroma regeneration . They rePark et al. utilized a topical cell-free conditioned medium derived from autologous ADSCs on murine models of alcohol-burn-induced keratitis . The ADSBone-marrow-derived mesenchymal tissue and ADSCs have been compared in several studies in the literature. Demirayak et al. created experimental models to study the mitigating effects of SCs on corneal scarring following penetrating injuries . They peADSCs have been the topic of several studies in the literature that examine the potential therapeutic options for these cells in retinal diseases. Rajashekar et al. found that intravitreal injection of ADSCs in streptozotocin-induced diabetic rats correlated with fewer signs of early vascular derangement characteristic of diabetic retinopathy (DR) . Safwat As with any surgical procedure, ADSC implantation has been assessed for potential risks to the retina. Limoli et al. recorded no complications and an improvement in scotopic electroretinographic scores following suprachoroidal grafting of mature adipocytes and ADSCs in the stromal vascular fraction enriched with platelet-rich plasma (PRP) amongst elderly patients with non-exudative age-related macular degeneration (AMD) . This grGenetic and tissue engineering has been hypothesized for the treatment of DR . Vision Rajashekar et al. proposed a strategy to regenerate the retinal vasculature and neuronal cell integrity via intravitreal injection of ADSCs in streptozotocin-induced murine models of early DR . ADSCs wIt has also been postulated that the administration of autologous ADSC exosomes to streptozotocin-induced diabetic rabbits could attenuate diabetic-retinopathy-related neurodegeneration and microvasculopathy via increased microRNA-222 expression . ElschaeADSCs are known to play a role in retinal and photoreceptor cell proliferation . hADSCs Late-phase optic nerve disease yields profound functional limitations, which usually tend to be irreversible . ADSCs, Experiments based on in vivo ADSC transplantation have shown possible therapeutic benefits in rat models with ameliorated optic nerve injury. Treatment showed signs of inhibiting insult-induced inflammation ,113. TheStudies have reported that ADSC therapy could be beneficial in thyroid-associated orbitopathy . It has Wu et al. reviewed the potential of iPSCs derived from autologous adipose tissue to forge patient-specific remedies for degenerative and acquired oculoplastic diseases . Lee et Negative outcomes have been reported by Fuentes-Julián et al., who sought methods to reduce the rejection of corneal grafts . They inOner et al. administered subretinal ADSCs in a small sample of patients with advanced retinitis pigmentosa. Post-implantation reports indicated that 54% of the study group developed complications around the site of implantation, and 90% of the study group reportedly showed no objective evidence of improved visual function post-therapy . KuriyanDeleterious effects of in vivo exogenous mesenchymal stem cell implantation have been reported to occur via myofibroblast proliferation around microvascular smooth muscle cells and pericytes . FindingCataract is one of the leading causes of avoidable visual impairment. ADSCs have the potential to offer future management strategies. ADSC exosomes have been found to attenuate UV-induced lenticular changes via the downregulation of cartilage acid protein-1, CRTAC1 . Zhou etThe further development of strategies to advance viable neuroectodermal progenitor cell extraction from orbital adipose tissue could broaden the range of differentiation of ADSCs, especially regarding their integration into non-mesenchymal ocular structures. Future studies could provide hope for the generation of viable tissues for corneal transplant without rejection. Studies unfortunately have yet to isolate ADSCs from specific orbital adipose tissue differentiated from the neural crest, from which corneal tissue also embryologically derives.Cytokine-primed MSCs expressing the anti-inflammatory protein TSG-6 could potentially find future applications in the clinical picture of idiopathic orbital inflammatory syndrome. Cytokine priming has also been suggested to have a role in retinal vasculopathies via cytokine-primed adipose stem cells’ protection against increased vascular endothelial permeability associated with DR . ExosomeEspandar et al. suggested that hADSCs possess the capacity to differentiate into keratocytes within the corneal stroma in animal models . This hoLimbal stem cell (LSC) insufficiency can present with severe visual deficits, including light sensitivity and pain . Human fThere is also promise in the use of ADSCs in managing individuals suffering from dry eye disease. A study on canines showed that injecting ADSCs into the lacrimal glands resulted in a significant increase in tear volume as measured by Schirmer’s test . Alió DeIn addition to their abundance, the minimally invasive approach for obtaining ADSCs renders these cells an interesting and viable option in various treatment regimens in ophthalmology. The multicellular lineage of ADSCs also provides the required diversity for ophthalmic applications. The adoption of ADSC therapies for refractory inflammatory and degenerative eye diseases holds great promise, considering the extensive differentiation capacities and secreted paracrine factors of ADSCs. Several studies in the literature, however, have reported the potential for unregulated cell proliferation when using these cells; thus, future long-term results are needed to explore the possible neoplastic effects of these cells when used for treatment. Caution is of utmost importance when considering cell-based therapies in human subjects, especially when treatment involves invasive and/or posterior segment delivery.


This study clearly establishes how low viral diversity limits the utility of genomic methods of epidemiological inference for SARS-CoV-2.Tracking the spread of infection amongst individuals within and between communities has been a major challenge during viral outbreaks. With the unprecedented scale of viral sequence data collection during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the possibility of using phylogenetics to reconstruct past transmission events has been explored as a more rigorous alternative to traditional contact tracing; however, the reliability of sequence-based inference of transmission networks has yet to be directly evaluated. E. E. Bendall, G. Paz-Bailey, G. A. Santiago, C. A. Porucznik, et al. (mSphere 7:e00400-22, 2022,  The mapping of transmission networks is a powerful tool for understanding pathogen dynamics during an outbreak. While these networks have often been constructed using traditional contact tracing methods , 2, phylStaphylococcus aureus in regions across the globe  pandemic, sequence-based inference has been used to identify superspreading events , track g17–Bendall et al. used SARS-CoV-2 sequence data from households where transmission events between close contacts could be determined with high confidence to determine whether sequences from within a known transmission cluster are more similar to each other than to sequences from the broader community . This apDrawing on samples collected from three distinct household transmission studies, the authors constructed phylogenetic trees comprised of SARS-CoV-2 sequences from study participants alongside sequences from the surrounding communities. The amount of community sequence data included on each tree was determined by estimating the overall sampling densities in each study region . Though sequences sampled from participants within a household generally grouped together on a phylogenetic tree, these clusters were often interspersed with other  sequences from the surrounding community that were unlikely to be directly linked by transmission. In a situation where the probable transmission linkages were not already known, this lack of differential clustering would confound efforts to accurately resolve transmission chains. The low levels of SARS-CoV-2 genetic diversity within communities thus hinders the detection of transmission chains from sequence data.The authors also asked whether including subconsensus genetic variants in sequence comparisons could improve efforts to match linked samples by providing an additional level of genetic diversity. They found that the inclusion of subconsensus variants was not always sufficient to resolve known transmission linkages from a larger pool of community sequences. Therefore, while sequence comparisons could confirm transmission between individuals who were already known to be epidemiologically linked , Bendall et al. show that phylogenetic clustering is not sufficient to confidently determine SARS-CoV-2 transmission linkage in the absence of supplemental contact tracing information.This study highlights important limitations that should be taken into consideration when reconstructing SARS-CoV-2 transmission networks based on sequence data alone. While the authors note that their results may not translate to congregate settings with higher infection densities, the lack of viral diversity observed in more dispersed communities poses a challenge to epidemiological inference. These findings suggest that sequence data should be used to help confirm likely SARS-CoV-2 transmission events, rather than to identify new ones. Furthermore, the authors demonstrate that phylodynamic methods cannot be applied to all infectious agents with equal effectiveness. The background population diversity and underlying biology of the pathogen of interest must be considered before attempting to draw epidemiological conclusions from sequence data.


Acute and chronic lung diseases are a leading cause of morbidity and mortality globally. Unfortunately, these diseases are increasing in frequency and we have limited treatment options for severe lung diseases. New therapies are needed that not only treat symptoms or slow disease progression, but also enable the regeneration of functional lung tissue. Both airways and alveoli contain populations of epithelial stem cells with the potential to self-renew and produce differentiated progeny. Understanding the mechanisms that determine the behaviour of these cells, and their interactions with their niches, will allow future generations of respiratory therapies that protect the lungs from disease onset, promote regeneration from endogenous stem cells or enable regeneration through the delivery of exogenous cells. This review summarises progress towards each of these goals, highlighting the challenges and opportunities of developing pro-regenerative (bio)pharmaceutical, gene and cell therapies for respiratory diseases. Summary: Lung regeneration by tissue-resident stem cells represents a therapeutic target to reverse the functional decline of lung tissue in respiratory diseases. This review covers approaches to improve regenerative outcomes by promoting the function of endogenous cells, creating a regeneration-competent microenvironment or applying exogenous stem cells in cell therapy approaches. Approximately 7.4% of the human population are currently affected by a chronic lung disease, making respiratory disease a major cause of morbidity and mortality globally . PatholoCurrent therapies for progressive lung diseases target inflammation, bronchoconstriction or fibrosis, with a view to slowing disease progression and/or controlling symptoms. During end-stage lung disease, heart–lung transplantation can provide an extreme option to provide patients with healthy lung tissue but donor shortages, immunosuppression and the risk of rejection remain significant limitations of this approach. Since no therapy has yet proved capable of reversing established disease, the generation of ‘pro-regenerative’ therapies – those that actively promote wound healing and tissue repair to increase the volume of functional tissue – is a major aim for the field. A pro-regenerative effect could be achieved by modulating lung stem cell function, for example by protecting or stimulating endogenous stem cells, or by engrafting exogenous stem cells. Such a therapy could provide an entirely novel approach or act as an adjunct to existing therapies.in vitro modelling using human cell models, in vivo animal models, and technological advances. In light of this recent progress, this article reviews existing and potential approaches to modulating epithelial regeneration in the lung as a route to preventing or treating respiratory diseases.Over the last two decades, significant progress has been made in understanding the cellular and molecular basis of lung regeneration through a combination of improved The epithelia of the nose, larynx, trachea, bronchi and alveolus are important interfaces with the outside world. These barriers are charged with host defence against inhaled pathogens and particulates, as well as enabling pulmonary gas exchange. During homeostasis, the turnover of the airway and lung epithelia is relatively low compared to skin or gut epithelia, but region-specific stem cell populations maintain lung epithelia and repair them following injury  Basil e.Human proximal airways are lined by a pseudostratified epithelium that is maintained by TP63-expressing basal stem cells . ComparaAt airway termini, respiratory bronchioles containing simple columnar epithelium bridge the airway and alveolar compartments. Human respiratory bronchioles contain a population of secretory progenitor cells with the capability to generate alveolar type II (AT2) in organoid models . The plaIn the alveolus, the epithelium consists of alveolar type I (AT1) and AT2 cells, which are specified during embryonic development and continue to mature following birth. AT1 cells are large, thin cells that provide the majority of the alveolar surface area at the interface between air and pulmonary capillaries. AT2 cells are comparatively small, cuboidal in shape and are responsible for the synthesis and secretion of pulmonary surfactant. AT2 cells can proliferate during postnatal life, giving rise to AT1 and AT2 cell populations . While AIn COPD, chronic small airway inflammation leads to airway wall thickening and fibrosis . ProgresWhile these therapies do not target epithelial stem cell populations directly, all are likely to impact epithelial homeostasis and/or repair. For example, while corticosteroids are used to curb inflammation in COPD, they are also used foetal lung maturation in women at risk of preterm delivery . In the Bronchodilators are used to decrease resistance in the lung and improve airflow. Broadly, these drugs either inhibit cholinergic or activate β2-adrenoreceptors (β-ARs) to induce the relaxation of airway smooth muscle. The muscarinic receptors targeted by anti-cholinergic bronchodilators are also expressed on airway epithelial cells, including ciliated cells where they regulate ciliary beat frequency. Though expressed by basal stem cells, any role muscarinic receptors have in stem cell function is so far uncharacterised. β2-agonist bronchodilators – which are the most heavily prescribed bronchodilators for asthma – activate receptors on airway smooth muscle cells to relax airways. However, activation of the same receptors on epithelial cells contributes to the inflammation, mucous metaplasia and airway hyperresponsiveness associated with asthma . MoreoveIn 2014, the small molecules pirfenidone and nintedinab were approved as anti-fibrotic therapies for pulmonary fibrosis. Pirfenidone was identified as an anti-inflammatory compound and was later shown to be anti-fibrotic in animal models . While iOverall, the effects of clinical therapies on lung regeneration are currently only partially understood and furthering this understanding might enable combination therapies that reduce inflammation and/or fibrosis as well as potentiate epithelial repair.Ultimately, progress in the treatment of established chronic lung diseases will require therapies that actively promote lung repair and regeneration to reverse tissue damage. The ability to modulate stem cell proliferation, migration and/or differentiation would be beneficial to this aim. We increasingly understand the signals that control lung stem cell behaviour and these mechanisms often mirror those used during lung development .A range of cell types contribute to a complex microenvironment in which lung regeneration occurs; lung epithelial stem cell niches consist of differentiated epithelial cells , mesenchin vitro studies suggested that RA pathway activation in fact decreased lung epithelial organoid size while pathway inhibition could increase epithelial cell proliferation  stimulated alveolar repair in an elastase-induced emphysema model in rats  led to cferation . Moreoveferation , suggestThe example of ATRA speaks to a wider challenge in developing a pro-regenerative therapy, rather than one that alleviates symptoms or slows disease progression: a single intervention can have conflicting effects on different lung cell types. This is exemplified by work that identifies the EGFR signalling pathway as a potential target in chronic lung disease. Inducible lung epithelial expression of TGF-α can drive lung fibrosis , while sLung epithelial regeneration has been improved in animal studies using both biopharmaceuticals and small molecule approaches. Biopharmaceutical approaches shown to increase epithelial cell proliferation after lung injury have included keratinocyte growth factor KGF,  and vascin vivo are not known and our understanding of the mechanisms that control cell movement is limited.Several other aspects of lung epithelial biology might offer new approaches to promoting lung regeneration. First, the remarkable plasticity of cells following injury may enable the reprogramming of differentiated epithelial cells to a stem cell state. Cells committed to a secretory fate are able to regenerate mouse airways following extreme damage , AT1 celSo far, this review has considered approaches to encourage regeneration by resident stem cells directly. However, modulating the lung microenvironment or protecting stem cells from local inflammation might also prove effective in improving regenerative outcomes and/or avoiding the initiation of damaging feed-forward cycles that drive disease progression.Skeletal stem cells (SSCs) – or ‘mesenchymal stromal cells’ (MSCs) – isolated from the bone marrow have been investigated as cell therapies in a wide range of settings due to their ease of isolation and expansion . In lungDuring homeostasis and wound healing, growth factors produced by fibroblasts are key niche factors, but their expression is abnormally low in diseased lung tissue . KnockdoSince chronic inflammation is a feature of the lung stem cell niche in both ageing and chronic lung disease, this also represents a target to improve the regenerative microenvironment. For example, the inflammatory cytokine interleukin 1 beta (IL-1β) is elevated in bronchoalveolar lavage fluid from healthy smokers  and IPF A further major alteration to the stem cell niche that occurs during both ageing and chronic lung diseases is the onset of cellular senescence. Senescence-associated phenotypic changes, such as cell cycle arrest and senescence-associated secretory phenotypes, are likely to have evolved at least in part to limit regeneration from damaged cells by encouraging their clearance by the immune system, thus promoting productive tissue repair following acute injury . HoweverGenomic analysis of human airway basal cells revealed that tobacco smoking leads to increased genomic damage with a high degree of cell-to-cell variability such that some basal cells remain relatively spared while others carry thousands of mutations . Importaex vivo might overcome some of the limitations of gene therapy, such as the physical barrier to transduction posed by airway mucous and luminal epithelial cells  transplantation, is an approved therapy in the context of haematopoietic malignancies, while epithelial stem cells have been successfully employed for severe burns injuries and limbal stem cell insufficiency . For a sin vivo poses a further challenge. Learning from other epithelial tissues, we now appreciate that maintaining stem cells with long-term repopulating capacity through culture steps determines graft outcome  gene (reviewed in Overall, substantial progress has been made towards cell-based therapy in the lung over the past decade and focussed pre-clinical work on pre-conditioning, model development and cell delivery are likely to lead to translational breakthroughs. Substantial progress is also being made in the field of lung bioengineering (reviewed in To date, the regenerative medicine approach has seen limited clinical application in respiratory medicine. However, strategies are being developed to protect healthy lung tissue prior to the inception of disease, to promote the function of endogenous lung stem cells either directly or through host microenvironmental modification, and to initiate repair using exogenous autologous epithelial cell transplantation . As wellNumerous issues will be vital for the advancement of pro-regenerative medicines in the lung context. First, emerging 3D models of human lung tissue can be used to better understand the considerable heterogeneity of regenerative responses between individual patients. Second, creating a microenvironment to foster regeneration within the lung might improve outcomes with existing or novel therapeutics. A better understanding of lung epithelial-immune interactions during development and resolving repair would be beneficial in this context, as would a more comprehensive understanding of the role of ageing in lung regeneration. Finally, successful pre-clinical lung epithelial cell expansion protocols will need modification in terms of GMP manufacture, scale and transplantation methods before clinical benefit. In the longer term, these data will also be informative for tissue- and organ-scale bioengineering applications.