Controversies in orthopaedic oncology

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Initial Six Month's Study of Neonatal Covid-19 in a Tertiary Care Hospital of Bangladesh

The pandemic Covid-19 affects mainly adult causing fatal illness specially who have co-morbidities. But as days pass by with increasing surveillances it's gradually obvious that this devastating disease also affects the children as well as neonates with greater number. The aim of study was to determine the Covid-19 in neonates. So, we can give proper emphasis on neonatal Covid-19. This cross-sectional study was conducted from April 2020 to September 2020 at Dhaka Shishu (Children) Hospital in Bangladesh. Neonates with suspected Covid-19 were tested for SARS-CoV-2 by RT- PCR. Newborn who had suspected or confirmed COVID-19 mother, exposed to relatives infected with Covid-19, related with cluster outbreak or with abnormal clinical courses such as respiratory distress, not responded to conventional treatment and also abnormal chest x-ray was selected for Covid-19 test. Data regarding gestational age, birth weight, gender, positive cases and other findings were collected and analyzed. Statistics analysis was done by SPSS version 26.0. Forty three cases were Covid-19 positive. Among them 28(65.1%) cases were male and 15(34.9%) female. Term was 39(90.6%) cases and preterm 4(9.4%). Twenty nine (67.5%) cases were belonged to medicine and 14(32.6%) surgical cases. Fourteen (32.5%) cases with Covid-19 lived in Dhaka and 29(67.5%) cases in outside of Dhaka. Eleven (25.5%) cases were positive for SARS -CoV-2 by RT- PCR within 3 days, among them 5 (11.6%) cases were within 24 hours of age. Nine (20.9%) and 23(53.5%) cases were test positive at day 4-7 and 8-28 days respectively. The main symptoms at admission were respiratory difficulty (12/43, 27.9%), fever (8/43, 18.6%), convulsion (8/43, 18.6%) and reluctance to feed (7/43, 16.6%). In neonate two or more diseases coexist in same cases. Sepsis was present in 20 (46.5%) cases with COVID-19. Perinatal asphyxia was present in 10(23.3%) and pneumonia in 8 (18.6%) cases. In laboratory findings low Hb% was present in 2/43(4.7%) cases, leukopenia in 4/43(9.3%), leukocytosis in 2/43(4.7%) and thrombocytopenia in 5/43(11.6%). Elevated CRP was present in 14/29 (32.6%) cases, hypernatremia in 10/33 (30.3%), hyponatremia in 1/33(3%), increased serum creatinine in 10/18(55.6%), and prolonged PT, aPTT in 2/2(100%). Hyperglycaemia was found in 1/15(6.7%) cases and hypoglycaemia in 2/15(13.3%). No organism was found in blood C/S. In chest X-ray, one showed patchy opacities in right lower lobe, another showed bilateral ground-glass opacity and third one revealed few patchy opacities in the right perihilar region. Among 43 cases 21(48.9%) were discharged with advice, 12(27.9%) cases referred to Covid-19 designated hospital, 2(4.7%) cases LAMA (Leave against medical advice) and 8(18.6%) cases died including one surgical case. A good number (43) of Covid-19 cases were found in this study. In neonates the clinical features could not be differentiated properly between Covid-19 or associated diseases unlike children and adult. The neonate may be a source of transmission of this disease. So, we should give proper emphasis on test, tracing and management of neonatal Covid-19.

Nonlinear Reactor Design Optimization With Embedded Microkinetic Model Information

Despite the success of multiscale modeling in science and engineering, embedding molecular-level information into nonlinear reactor design and control optimization problems remains challenging. In this work, we propose a computationally tractable scale-bridging approach that incorporates information from multi-product microkinetic (MK) models with thousands of rates and chemical species into nonlinear reactor design optimization problems. We demonstrate reduced-order kinetic (ROK) modeling approaches for catalytic oligomerization in shale gas processing. We assemble a library of six candidate ROK models based on literature and MK model structure. We find that three metrics—quality of fit (e.g., mean squared logarithmic error), thermodynamic consistency (e.g., low conversion of exothermic reactions at high temperatures), and model identifiability—are all necessary to train and select ROK models. The ROK models that closely mimic the structure of the MK model offer the best compromise to emulate the product distribution. Using the four best ROK models, we optimize the temperature profiles in staged reactors to maximize conversions to heavier oligomerization products. The optimal temperature starts at 630–900K and monotonically decreases to approximately 560 K in the final stage, depending on the choice of ROK model. For all models, staging increases heavier olefin production by 2.5% and there is minimal benefit to more than four stages. The choice of ROK model, i.e., model-form uncertainty, results in a 22% difference in the objective function, which is twice the impact of parametric uncertainty; we demonstrate sequential eigendecomposition of the Fisher information matrix to identify and fix sloppy model parameters, which allows for more reliable estimation of the covariance of the identifiable calibrated model parameters. First-order uncertainty propagation determines this parametric uncertainty induces less than a 10% variability in the reactor optimization objective function. This result highlights the importance of quantifying model-form uncertainty, in addition to parametric uncertainty, in multi-scale reactor and process design and optimization. Moreover, the fast dynamic optimization solution times suggest the ROK strategy is suitable for incorporating molecular information in sequential modular or equation-oriented process simulation and optimization frameworks.

Thirty-day mortality following surgical management of hip fractures during the COVID-19 pandemic: findings from a prospective multi-centre UK study

PURPOSE

Thirty-day mortality of patients with hip fracture is well researched and predictive; validated scoring tools have been developed (Nottingham Hip Fracture Score, NHFS). COVID-19 has significantly greater mortality in the elderly and comorbid patients which includes hip fracture patients. Non-operative treatment is not appropriate due to significantly higher mortality, and therefore, these patients are often exposed to COVID-19 in the peri-operative period. What is unclear is the effect of concomitant COVID-19 infection in these patients.

METHODS

A multicentre prospective study across ten sites in the United Kingdom (responsible for 7% of hip fracture patients per annum in the UK). Demographic and background information were collected by independent chart review. Data on surgical factors included American Society of Anesthesiologists (ASA) score, time to theatre, Nottingham Hip fracture score (NHFS) and classification of fracture were also collected between 1st March 2020 and 30th April 2020 with a matched cohort from the same period in 2019.

RESULTS

Actual and expected 30-day mortality was found to be significantly higher than expected for 2020 COVID-19 positive patients (RR 3.00 95% CI 1.57-5.75, p < 0.001), with 30 observed deaths compared against the 10 expected from NHFS risk stratification.

CONCLUSION

COVID-19 infection appears to be an independent risk factor for increased mortality in hip fracture patients. Whilst non-operative management of these fractures is not suggested due to the documented increased risks and mortality, this study provides evidence to the emerging literature of the severity of COVID-19 infection in surgical patients and the potential impact of COVID-19 on elective surgical patients in the peri-operative period.

Expression of the matrix metalloproteinases MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2 in systemic lupus erythematosus patients

BACKGROUND

The study aimed to look at alterations in expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) and their potential use as biomarkers in the pathogensis of SLE.

METHODS

SLE patients (n = 41) and healthy controls (n = 50) were recruited. Quantitative RT-PCR/ELISA assays were performed for expression of MMP and TIMP mRNA in whole blood and PBMC; and corresponding serum protein levels. Intracellular levels of MMP-2 and MMP-9 proteins were analysed by flow cytometry.

RESULTS

Based on SLEDAI scores patients were grouped into active (SLEDAI ≥ 10) and inactive cases (SLEDAI < 10). In active cases, MMP-2 expression significantly increased and TIMP-2 expression was decreased (p < 0.0001) both at serum secretion (p = 0.0003) and mRNA (p < 0.0001) levels as compared to inactive cases. MMP-9 and TIMP-1 showed significantly reduced serum secretion and mRNA expression (p < 0.0001) in active cases as compared to inactive cases. Intracellular concentration of MMP-9 was reported to be higher in neutrophils, while MMP-2 was mainly found in lymphocytes of SLE patients as compared to controls. MMP/TIMP ratio profile was altered as SLE disease progresses.

INTERPRETATION & CONCLUSIONS

Findings suggest disturbed MMP and TIMP levels have a role in the pathogenesis of SLE.

Identification of structural fingerprints for ABCG2 inhibition by using Monte Carlo optimization, Bayesian classification, and structural and physicochemical interpretation (SPCI) analysis

The human breast cancer resistance protein (BCRP), one of the members of the large ATP binding cassette (ABC) transporter superfamily, is crucial for resistance against chemotherapeutic agents. Currently, it has been emerged as one of the best biological targets for the designing of small molecule drugs capable of eliminating multidrug resistance in breast cancer. In order to gain insights into the relationship between the molecular structure of compounds and the ABCG2 inhibition, a multi-QSAR approach using different methods was performed on a dataset of 294 ABCG2 inhibitors with diverse scaffolds. The best models obtained by different chemometric methods have the following statistical characteristics: Monte Carlo Optimization-based QSAR (sensitivity = 0.905, specificity = 0.6255, accuracy = 0.756, and MCC = 0.545), Bayesian classification model (sensitivity = 0.735, specificity = 0.775, and concordance = 0.757); structural and physicochemical interpretation analysis-random forest method (balance accuracy = 0.750, sensitivity = 0.810, and specificity = 0.700). Additionally, structural fingerprints modulating the ABCG2 inhibitory properties were identified from the best models of each method and also validated with each other. The current modelling study is an attempt to get a deep insight into the different important structural fingerprints modulating ABCG2 inhibition.

Do high sensitivity C-reactive protein and serum interleukin-6 levels correlate with disease activity in systemic lupus erythematosuspatients?

Introduction:

Systemic Lupus Erythematosus (SLE) is an inflammatory autoimmune disease where an interplay between acute phase proteins and cytokines are involved in disease activation.

Aim and Objectives:

This case control study was performed to investigate interrelationship between high sensitivity C-reactive proteins (hs-CRP), Interleukin-6 (IL-6) levels and disease activity among SLE patients.

Materials and Methods:

One hundred forty one clinically diagnosed SLE cases were included and disease activity was noted by SLE Disease Activity Index (SLEDAI). Serum IL-6 levels were measure by cytokine multiplex assay. Serum hs-CRP, C3 and C4 levels were measure by nephelometer. The Pearson correlation test was used for correlation between hs-CRP, Il-6 and SLEDAI.

Results:

Based on SLEDAI, 126 patients (89.4 %) had active disease and 15 patients (10.6%) had inactive disease. Mean hs-CRP levels in SLE patients were significantly higher (12.1+ 11.5 mg/L) than controls (2.41+ 1.37 mg/L) (P < 0.0001). Hs-CRP levels among active SLE were significantly higher (13.5+ 11.4 mg/L) as compared with inactive SLE (4.4 + 2.9 mg/L) (P=0.0002). Similarly, IL-6 levels in SLE patients were significantly higher among active SLE (26.9 + 15.5 pg/ml) as compared with inactive SLE (13.9+ 10.2 pg/ml) (P=0.0001). An inverse correlation between Il-6 and hemoglobin levels between active and inactive SLE was noted (r=-0.46, P <0.0001).

Conclusion:

This study suggests a good correlation between hs-CRP, IL-6 and SLE disease activity indicating their direct involvement in inflammatory conditions associated with disease.

Impact of functional IL-18 polymorphisms on genetic predisposition and diverse clinical manifestations of the disease in Indian SLE patients

Several studies have demonstrated associations between interleukin-18 polymorphisms and risk of systemic lupus erythematosus in different populations except one of Indian origin. We therefore investigated for the influence of interleukin-18 (-1297T/C, -607A/C, -137G/C; + 105A/C) polymorphisms on genetic susceptibility and clinical expression of the disease in Indian systemic lupus erythematosus patients. A total of 200 systemic lupus erythematosus patients and 201 controls were recruited. Genotyping of interleukin-18 polymorphisms were performed by polymerase chain reaction-restriction fragment length polymorphism. Serum interleukin-18 levels were measured by enzyme-linked immunosorbent assay. Interleukin-18 (-1297T/C; -137G/C) polymorphisms showed significant association with genetic susceptibility to the disease in our systemic lupus erythematosus cohort. Stratification analysis revealed -1297CC and -1297C associated with renal involvement (odds ratio = 3.4, correcting p value = 0.0207), (odds ratio = 2.0, correcting p value = 0.0054) respectively. Additionally, -1297C allele frequency was significantly increased in patients with anti-nucleosome antibody (odds ratio = 2.1, correcting p value = 0.0301). Haplotype analysis showed CC haplotype strongly associated with serositis (odds ratio = 9.1, correcting p values = 0.0009) and neurologic involvement (odds ratio = 9.3, correcting p value = 0.0018). We reported a 2.7-fold increase in serum interleukin-18 levels in patients (511.5 ± 242.3 pg/ml) compared to controls (189.4 ± 80.8 pg/ml) ( p < 0.0001). Furthermore, interleukin-18 levels were positively correlated with disease activity ( r = 0.548, p = 0.0001) and renal involvement in the patients with lupus nephritis ( r = 0.569, p < 0.0001). In summary, interleukin-18 polymorphisms elucidated in this study appear to confer genetic susceptibility to the disease and are associated with renal, serositis and neurologic involvement in Indian systemic lupus erythematosus patients.

Effects of probiotics-encapsulated live feed on growth and survival of juvenile Clarias batrachus (Linnaeus, 1758) after differential exposure to pathogenic bacteria

Growth and survival of Clarias batrachus juveniles (10-day old) fed probiotic Bacillus cereus (KR809412) encapsulated live feed (chironomid larvae) have been evaluated after differential exposure to the pathogenic Aeromonas hydrophila (MTCC 1739). Catfish juveniles were stocked at a density of 30 fish per tank in five experimental groups (T1-T5) along with a control group in triplicate and fed twice @ 5% of body weight day-1 for four weeks. Groups T1 and T2 were fed probiotic-encapsulated (PR) or pathogen-inoculated (PGN) live feed respectively, for initial three weeks. During this period groups T3 (PGN-PR-PR), T4 (PR-PGN-PR), and T5 (PR-PR-PGN) were differentially exposed to the pathogen. Live feed without probiotic and pathogen was offered to the control group throughout the experimental period and all other treatment groups (T1-T5) during the 4th week. Continuous exposure to probiotics in group T1 resulted in significantly higher (P<0.05) specific growth rate (SGR, % d-1) and survivability than other groups, whereas, pathogen exposed and probiotic deprived group (T2) noticed with the lowest SGR and the highest mortality. Among other treatment groups (T3, T4 and T5), group T4 resulted in improved SGR and survivability. The coefficient (r value) of 0.867 along with regression slope suggested a positive correlation (0.01 levels) between RNA: DNA and SGR. The study might suggest protective effects of probiotic B. cereus in pathogen exposed C. batrachus juveniles.SAARC J. Agri., 16(1): 105-113 (2018)

Tibiofemoral forces for the native and post-arthroplasty knee: relationship to maximal laxity through a functional arc of motion

PURPOSE

Accurate soft tissue balance must be achieved to improve functional outcome after total knee arthroplasty (TKA). Sensor-integrated tibial trials have been introduced that allow real-time measurement of tibiofemoral kinematics during TKA. This study examined the interplay between tibiofemoral force and laxity, under defined intraoperative conditions, so as to quantify the kinematic behaviour of the CR femoral single-radius knee.

METHODS

TKA was undertaken in eight loaded cadaveric specimens. Computer navigation in combination with sensor data defined laxity and tibiofemoral contact force, respectively, during manual laxity testing. Fixed-effect linear modelling allowed quantification of the effect for flexion angle, direction of movement and TKA implantation upon the knee.

RESULTS

An inverse relationship between laxity and contact force was demonstrated. With flexion, laxity increased as contact force decreased under manual stress. Change in laxity was significant beyond 30° for coronal plane laxity and beyond 60° for rotatory laxity (p < 0.01). Rotational stress in mid-flexion demonstrated the greatest mismatch in inter-compartmental forces. Contact point position over the tibial sensor demonstrated paradoxical roll-forward with knee flexion.

CONCLUSION

Traditional balancing techniques may not reliably equate to uniform laxity or contact forces across the tibiofemoral joint through a range of flexion and argue for the role of per-operative sensor use to aid final balancing of the knee.

Aromatase expression in atypical ductal hyperplasia in women

PURPOSE

To determine the levels of aromatase in atypical ductal hyperplasia (ADH) lesions, tissue surrounding the ADH, and in dense and non-dense normal breast tissue. We postulated that excess aromatase in breast tissue might, through production of increased estrogen, drive the carcinogenic process. Estrogens and their metabolites are thought to contribute to the development of breast cancer through estrogen receptor-mediated mechanisms and genotoxic effects of estrogen metabolites. ADH is a benign lesion of the breast which is associated with substantially increased risk for subsequent development of breast cancer. After 25 years, approximately 30% of women with ADH develop breast cancer. In women with three or more separate ADH lesions at the same time, 47% will develop breast cancer over that time period. Another important risk factor for breast cancer is the presence of mammographically dense breast tissue.

METHODS

We utilized quantitative immunochemical analysis of aromatase in biopsy tissue to test this possibility. Previously published results comparing dense with non-dense breast tissue in normal women (Vachon et al. Breast Cancer Res Treat 125:243-252, 2011) were used for comparisons with ADH. A well-characterized histochemical H-score was employed for quantitative assessment of aromatase in the various tissue studied.

RESULTS

The H-score of aromatase staining was statistically significantly higher (p = 0.003) in the ADH epithelium than surrounding epithelial tissue. In order of H-score from highest to lowest were ADH, issue surrounding ADH, dense normal and non-dense normal breast tissues. The levels of aromatase in a subset of women with ADH who went on to develop breast cancer were not higher than in women who did not.

CONCLUSIONS

We suggest from these studies that overexpression of aromatase in breast tissue and its resultant increase in estradiol levels may contribute to the later development of breast cancer in women with ADH.

Abstract P1-02-08: Provista-002: A prospective, multi-center study to determine the effectiveness of a biomarker assay to distinguish benign from invasive breast cancer in women with BI-RADS 3, 4 and 5 imaging reports

This abstract was not presented at the symposium.

Abstract P4-17-02: Design, implementation and evaluation of a smoking cessation intervention for patients undergoing breast cancer surgery

Introduction:

Smoking is a risk factor for poor outcomes following breast reconstructive surgery, including wound dehiscence and infection. Women who would choose to have reconstructive surgery after mastectomy for breast cancer are unable to do so if they have not quit smoking. The specific aims of this project are to 1) design and implement an intervention to assist these patients in quitting and 2) evaluate its efficacy.

Methods:

Baseline data regarding current practices was collected via a chart review of 75 smoking breast cancer surgery patients from 1/1/2012-12/31/13. Charts were analyzed for documentation of smoking status, quit advice, resources provided and used, and smoking status at follow-up. Formative research informed the design of an Ask-Advise-Refer intervention for all new breast cancer patients seen at Mayo Clinic.

Intervention Design:

Smoking patients were identified prior to their initial Breast Cancer evaluation at Mayo Clinic, Rochester, during a standard intake call. Smoking status was documented by the rooming assistant to alert the physicians of smoking status, and physicians asked these patients about their smoking behavior, discussed the risks of smoking both for surgical procedures and breast cancer, and offered a Nicotine Dependence Consultation with a tobacco treatment specialist in an “opt-out” strategy that emphasized the importance of smoking cessation as part of the breast cancer treatment process. The advice and referral was documented in the medical record. Evaluation of the intervention was performed via a chart review of patients seen after one year of implementation.

Intervention Evaluation Results:

Breast clinic physicians documented smoking status in all patients seen after implementation. Referral to the Nicotine Dependence Center for cessation counseling increased from 29% (22/75) to 74% (20/27). Among those referred, attendance at the consultation increased from 41% (9/22) to 75% (15/20), suggesting stronger provider encouragement of cessation services. 30-day abstinence rates for those who attended a consult prior to 5/1/16 were 46% (6/13), which is consistent with baseline data.

Conclusions:

An Ask-Advise-Refer intervention for new breast cancer patients seen at Mayo Clinic, Rochester, who report current smoking, has been associated with higher rates of provider counseling on tobacco dependence, referral to available services, and patient attendance at referrals. Attending a referral greatly increases a patient's chances of quitting smoking for at least 30 days compared to average spontaneous quit rates in this population. This model is low-cost, time-efficient for providers, and applicable to most practice settings. Finding ways to make this intervention self-sustaining and applicable to multiple other practices could greatly improve our patient's health outcomes.

Citation Format: Nolan M, Ghosh K, Warner DO. Design, implementation and evaluation of a smoking cessation intervention for patients undergoing breast cancer surgery [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-17-02.

Role of MMP-7 in the pathogenesis of systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a clinically heterogeneous chronic, inflammatory autoimmune disorder. The association of MMP-7 and disease severity is still unclear. A total of 150 SLE patients and matched healthy controls were recruited for this study. Disease activity was scored according to SLEDAI (98 active and 52 inactive disease). Mean serum MMP-7 levels were significantly higher in SLE patients than controls ( p < 0.001). Patients with active disease showed higher levels (16.24 ± 6.2 ng/ml) as against inactive disease (10.50 ± 3.97 ng/ml) ( p ≤ 0.0001). Mean MMP-7 mRNA expression was significantly higher in patients (RQ = 3.16 ± 0.93) as compared to controls (RQ = 2.21 ± 0.89, p = 0.006). A positive correlation between MMP-7 levels, mRNA expression and SLEDAI score was observed ( r = 0.563, r = 0.427). The MMP-7 -181 G allele was found to be significantly higher among SLE patients ( p < 0.0001). A significant association was noted between MMP-7 -181 A/G +G/G genotypes with renal ( p = 0.0027) and CNS ( p = 0.0031) manifestations and anti-dsDNA autoantibodies ( p = 0.0312). Serum MMP-7 levels and mRNA expression were elevated in advanced stages of SLE, indicating that MMP-7 is associated with disease activity in SLE.

Individualization of antiretroviral therapy--pharmacogenomic aspect

Combination therapy with three drug regimens for human immunodeficiency virus (HIV) infection significantly suppresses the viral replication. However, this therapeutic impact is restricted by adverse drug events and response in terms of short and long term efficacy. There are multiple factors involved in different responses to antiretrovirals (ARVs) such as age, body weight, disease status, diet and heredity. Pharmacogenomics deals with individual genetic make-up and its role in drug efficacy and toxicity. In depth genetic research has provided evidence to predict the risk of developing certain toxicities for which personalized screening and surveillance protocols may be developed to prevent side effects. Here we describe the use of pharmacogenomics for optimal use of HAART (highly active antiretroviral therapy).

Amnion Epithelial Cells of Buffalo (Bubalus Bubalis) Term Placenta Expressed Embryonic Stem Cells Markers and Differentiated into Cells of Neurogenic Lineage In Vitro

Aim of the present study was the isolation, culture, and characterization of amniotic membrane-derived epithelial cells (AE) from term placenta collected postpartum in buffalo. We found that cultured cells were of polygonal in shape, resistance to trypsin digestion and expressed cytokeratin-18 indicating that they were of epithelial origin. These cells have negative expression of mesenchymal stem cell markers (CD29, CD44, and CD105) and positive for pluripotency marker (OCT4) genes indicated that cultured cells were not contaminated with mesenchymal stem cells. Immunofluorescence staining with pluripotent stem cell surface markers, SSEA-1, SSEA-4, TRA-1-60, and TRA-1-81 indicated that these cells may retain pluripotent stem cell characteristics even after long period of differentiation. Differentiation potential of these cells was determined by their potential to differentiate into cells of neurogenic lineages using retinoic acid. In conclusion, we demonstrate that AE cells expressed pluripotent stem cell markers and have propensity to differentiate into cells of neurogenic lineage upon directed differentiation in vitro.