Artificial intelligence as a precision tool for predicting risk of in-hospital death after aortic valve replacement

Background/Introduction

The prediction of risk of in-hospital death associated with cardiac surgery still has important gaps. In this scenario, the computational tools and mathematical techniques, the pillars of artificial intelligence, can represent an effective solution to this problem.

Purpose

To develop an in-hospital death prediction model for isolated aortic valve replacement (AVR) based on an artificial intelligence constituted by an artificial neural network (ANN).

Methods

352 patients consecutively submitted to isolated AVR between 2010 and 2020 were included. Altogether, 30 baseline variables were evaluated. Initially, the Extra Tree Classifier machine learning algorithm was used to select the attributes with the highest association with death. With the application of the algorithm, it was possible to identify the 11 variables with the greatest weight associated with in-hospital death. After selecting the variables and dividing the dataset into training (70%) and testing (30%), a risk prediction model was structured through an ANN with multiple layers. The ReLU activation function was used in the hidden layers and the SoftMax activation function was used in the output layer. As an optimizing function of the ANN, the Nadam function was used. In addition, a thousand cycles of propagation and data return (Epochs) were performed to induce machine learning based on the cyclic adjustment of the weights of each of the independent variables included in the model. Accuracy assessments were performed using the ROC curve in the test dataset. The model was developed using the Python programming language.

Results

A predictive accuracy of 93,6% (AUC 0,936) was observed for the occurrence of in-hospital death in the test dataset to the ANN. When comparing the performance of traditional risk scores, also tested only in the test dataset, we found that the ANN-based model was significantly superior to the scores (EuroScore I = 84,0% (AUC 0,840); EuroScore II = 84,4% (AUC 0,844), STS Score = 74,0% (AUC 0,740). The area under the curve of the model based on the ANN was significantly higher when compared to the areas of the scores using the DeLong test (p<0.05). When applying the same model only to patients aged 75 and over, the results were as follows: ANN AUC 0,877; ES1 AUC 0,652; ES2 AUC 0,590; STS AUC 0,663 (p<0,05).

Conclusion

The application of artificial intelligence modelling is feasible for the creation of prediction models in the health area. In this study, the accuracy of the ANN was significantly higher than that of the other traditional risk scores in the general sample and for patients with more advanced age. These findings demonstrate the great potential that representative datasets have when accessed through artificial intelligence techniques. The demand for massive volumes of information is mitigated when well-structured datasets with extreme data quality is used.

Funding Acknowledgement

Type of funding sources: None.

Artificial intelligence as a precision tool for predicting risk of in-hospital death after coronary artery bypass graft surgery

Background/Introduction

The prediction of risk of in-hospital death associated with cardiac surgery still has important gaps. In this scenario, the computational tools and mathematical techniques that constitute data science and provide machine learning, pillars of artificial intelligence, can represent an effective solution to this problem.

Purpose

To develop an in-hospital death prediction model for isolated CABG based on an artificial intelligence constituted by an artificial neural network (ANN).

Methods

3,124 patients consecutively submitted to isolated CABG between 2010 and 2020 were included. Altogether, 30 baseline and operative variables were evaluated. Initially, the Extra Tree Classifier machine learning algorithm was used to select the attributes with the highest association with death. With the application of the algorithm, it was possible to identify the 13 variables with the greatest weight associated with hospital death. After selecting the variables and dividing the dataset into training (70%) and testing (30%), a risk prediction model was structured through an ANN with multiple layers. The ReLU activation function was used in the hidden layers and the SoftMax activation function was used in the output layer to extract the specific probability of death and survival. As an optimizing function of the ANN, the Nadam function was used. In addition, a thousand cycles of propagation and data return (Epochs) were performed to induce machine learning based on the cyclic adjustment of the weights of each of the independent variables included in the model. Accuracy assessments were performed using the ROC curve in the test dataset. The model was developed using the Python programming language.

Results

After consolidating machine learning based on the training dataset with 70% of the general sample, it was possible to observe that through the artificial intelligence technique, a predictive accuracy of 83.86% (AUC 0.8386) was obtained for the occurrence of in-hospital death in the test dataset. When comparing the performance of traditional risk scores, also tested only in the test dataset, we found that the ANN-based model was significantly superior to the scores (EuroScore I = 71.4% (AUC 0.714); EuroScore II = 71.9% (AUC 0.719), STS Score = 71.1% (AUC 0.714). The area under the curve of the model based on the ANN was significantly higher when compared to the areas of the scores using the DeLong test (p<0.05)

Conclusion

The application of artificial intelligence modelling is feasible for the creation of prediction models in the health area. In this study, the accuracy of the ANN was significantly higher than that of the other traditional risk scores. These findings demonstrate the great potential that representative datasets have when accessed through artificial intelligence techniques. The demand for massive volumes of information is mitigated when well-structured datasets with extreme data quality is used.

Funding Acknowledgement

Type of funding sources: None.

Impact of atrial fibrillation on in-hospital outcomes of coronary artery bypass graft surgery: an analysis by propensity score matching

Background/Introduction

Many patients referred for coronary artery bypass graft (CABG) surgery have persistent or permanent atrial fibrillation (AF). Despite the significant occurrence, the impact of this arrythmia on surgical outcomes remains uncertain.

Purpose

To assess the impact of persistent or permanent AF on post-CABG in-hospital outcomes.

Methods

A cohort of 3,124 patients undergoing to isolated CABG between 2010 and 2020 was evaluated. A propensity score pairing was applied, considering persistent or permanent AF as a dependent variable and another 19 baseline characteristics as independent variables in the regression model used to build the propensity score. Pairing was performed at a ratio of 3:1 – Group 1: 324 patients without persistent or permanent AF; Group 2: 108 patients with the documented diagnosis of persistent or permanent AF. The statistical plan also included normality analyses, descriptive and univariate analyses, binary logistic regression, ROC curves and DeLong test to compare de curves. The significance level adopted was 5%. The analyses were performed by the programming language Python.

Results

None of the baseline characteristics evaluated showed a significant difference between the groups, including the EuroScore II (Group 1: 1.54±1.45 vs Group 2: 1.49±1.59; p=0.990). Likewise, none of the analysed surgical characteristics showed a significant difference, indicating a very approximate pattern of complexity of the surgeries. The absence of differences demonstrated a high degree of homogeneity between the groups. The use of pairing by propensity score aimed to form two extremely similar study groups, which differed only in relation to the diagnosis of the arrhythmia under study. Among the outcomes evaluated, AMI (1.5 vs 6.5; p=0.013), MACCE (7.1% vs 14.8%; p=0.015) and death (1.5% vs 6.5%; p=0.013) had significantly higher incidences in Group 2, formed by patients with persistent or permanent AF. From the multivariate analysis, it can be identified that permanent AF was an independent risk predictor for the occurrence of in-hospital death (OR: 5.009; 95% CI 1.433–17.507; p=0.012). Finally, it was also possible to verify that the association of EuroScore II with persistent or permanent AF showed higher predictive accuracy than EuroScore II alone (ESII+FA = AUC 0.852 vs ESII alone = AUC 0.775, p<0,05).

Conclusion(s)

Patients with persistent or permanent AF had significantly higher incidences of AMI, MACCE and in-hospital death. Persistent or permanent AF was characterized as an independent predictor for the occurrence of death and the association with the EuroScore II resulted in a 9.9% increase in the predictive accuracy of the surgical risk score.

Funding Acknowledgement

Type of funding sources: None.

Preoperative anaemia is an independent predictor of 30-day mortality post-CABG and improves de predictive accuracy of EuroScore II

Background

The impact of preoperative anaemia on the results of cardiovascular surgery has already been demonstrated by some authors. Some of the studies observed worse surgical results in anaemic patients, however, in others, no difference was observed. In addition, the impact that the inclusion of anaemia or haemoglobin would have as a predictor in a risk model such as EuroScore II is not yet known.

Purpose

To evaluate the impact of preoperative anaemia on 30-day mortality post-CRM and compare the predictive accuracy of EuroScore II with and without the inclusion of haemoglobin levels in the model.

Methods

Single center cohort with 2168 patients consecutively included between January 2010 and December 2020. All procedures were performed with cardiopulmonary bypass. 32 baseline and operative characteristics were assessed. The primary outcomes were 30-day mortality and the EuroScore II predictive accuracy. Patients were stratified into two groups according to anaemia status. WHO Classification – haemoglobin: men <13 g/dL and women <12 g/dL. No Anaemia Group (1301–60.1%) – Anaemia Group (867–39,9%). Univariate analysis was performed to compare the characteristics of the groups, the occurrence of death in 30 days and to verify variables associated with mortality. Logistic regression analyses were used to assess predictors of mortality and generate a set of probabilities for assessing the predictive accuracy of EuroScore II with and without the addition of haemoglobin in the model. The probabilities generated through the regressions were analysed by ROC curves, which in turn were compared using the DeLong test. The level of significance was 5% and the statistical analysis was performed using Python 3.0.

Results

The anaemic patients were older and had higher prevalence of conditions, such as: diabetes, renal impairment, smoking, HF class III or IV, RBC transfusion and highest mean of EuroScore II (p<0.05 for all conditions). When comparing mortality in the groups, a significantly higher rate was observed in the anaemic group (2.2% vs 5.4%; p<0.001). In view of the heterogeneity of the groups, an adjusted logistic regression model was applied. The results of the multivariate model demonstrated that preoperative anaemia was an independent risk predictor for the occurrence of death in 30 days after CABG (B: 0.597; SE: 0.27; Wald: 5.2; OR: 1.82; 95% CI 1.09–3.04; p=0.022). In addition, we were able to verify that the addition of preoperative haemoglobin to EuroScore II resulted in a significantly higher predictive accuracy when compared to the predictive accuracy of the isolated score (AUCs: 0,732 vs 0.709; p=0.032).

Conclusions

Preoperative anaemia was an independent risk predictor for the occurrence of death in 30 days after CABG. We were also able to verify that the addition of the preoperative haemoglobin levels to EuroScore II resulted in a significantly higher predictive accuracy, improving the performance of the surgical risk model.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Haemoglobin vs 30-day mortalityFigure 2. Predictive accuracies – EuroScore II

EuroScore II is the best predictive model for the off pump coronary artery bypass graft surgery

Background

Coronary artery bypass graft surgery (CABG) is the most common cardiac surgery performed in the world and a significant part of these surgeries are performed without cardiopulmonary bypass (off pump). Although none of the main surgical risk scores include pump use in their prediction model, the scores are widely used in risk stratification, including for patients who will be submitted to off pump CABG.

Purpose

To analyse and compare the predictive accuracy of EuroScore I, EuroScore II and STS Score for 30-day mortality after off pump CABG.

Methods

Single-centre cohort with 943 patients consecutively submitted to off pump CABG between January 2010 and December 2020. 31 baseline and operative variables were analysed. The primary outcome was the occurrence of death in the first 30 days after the surgery. Descriptive analysis, normality for quantitative data and univariate inference were performed to compare proportions and means between the survival group (n=930) and death group (n=13). Next, three logistic regression models were performed. Each of them had 30-day mortality as a dependent variable and one of the scores as an independent variable. The probabilities generated by the three models were saved and analysed by ROC curves. Thus, it was possible to assess the predictive accuracy of each of the scores. Finally, the values of the areas under the curves were compared using the DeLong test. The level of significance was 5% and the analysis was performed using the Python 3.0 programming language.

Results

The mean age of the general group was 63 years old and there was a predominance of male patients (68.4%). The means of the three evaluated risk scores were significantly higher in the Death group (p<0,05). This pattern confirmed the findings of higher prevalence of several comorbidities in the death group. The 30-day mortality rate was 1.37%. Through the analysis of regressions and the probabilities generated through them, it was possible to verify that the predictive accuracy of EuroScore II was significantly higher than that of the other two scores. While the predictive accuracy of EuroScore II was 77.3%, the accuracy of two other scores was in the range of 69% (AUC EsI: 0.697; AUC EsII: 0.773; AUC STS: 0.695; p=0.029).

Conclusion

EuroScore II seems to be the most adequate surgical risk score for the assessment of mortality risk of patients who will undergoing to off pump CABG. The score had a predictive accuracy of 77.3%, almost 8% more than the other two scores. Therefore, although EuroScore II does not include in its model the use of cardiopulmonary bypass, it has a satisfactory accuracy to be used in clinical-surgical practice. On the other hand, the EuroScore I and the STS Score showed predictive accuracy not adequate for this type of surgery.

Funding Acknowledgement

Type of funding sources: None. Predictive accuracies of risk scores

Results of on-pump and off-pump coronary artery bypass graft surgery in 30 days: an analysis by propensity score matching

Background

The results of coronary artery bypass graft surgery (CABG) performed with and without the support of cardiopulmonary bypass have already been widely discussed and studied, including through a few large randomized clinical trials. Despite the efforts, the findings of these studies still generate controversy and doubts about the outcomes achieved by the two techniques. One of the contested points is the heterogeneity of the degree of specialization in the off-pump technique in relation to the surgical groups that participated in the studies.

Purpose

To compare the results in 30 days of on-pump and off-pump CABG.

Methods

A single centre cohort with 1,767 patients undergoing isolated CABG was initially evaluated (January 2013 – December 2018). 397 patients undergoing off-pump CABG and 1,370 patients undergoing on-pump surgery were identified. To obtain two completely homogeneous study groups, a propensity score matching was applied. For this, a logistic regression model was built with the variable use of CPB support as dependent variable. In the group of independent variables, 14 baseline and operative characteristics were included. The probabilities generated for each patient were used as scores to establish the match. To establish a pair, it was necessary to have three squares after the comma, with the fourth decimal place being the tiebreaker criterion in the pairing. In this way it was possible to obtain 332 pairs (N=664). The paired groups, on and off-pump, were compared by descriptive and univariate analysis and later a logistic regression model was applied to identify possible risk predictors and to verify the impact of CPB support on 30-day mortality. The level of significance was 5% and the analysis was performed using Python 3.0.

Results

None of the 29 baseline and operative characteristics showed a significant difference between the groups, demonstrating a high degree of homogeneity obtained from the propensity score matching, which enabled a solid comparison between the incidences of outcomes in 30 days. None of the analysed outcomes showed any difference between the groups on and off-pump, including AMI, stroke, major reoperation and death (1.5% vs 2.4%; p=0.401). Through regression analysis it was possible to establish that the use of CPB was not an independent predictor of risk for the occurrence of death (p=0.246).

Conclusion

After matching by propensity score, patients who underwent surgery with and without CPB had similar incidences of 30-day mortality. In addition, it was possible to verify that the use of CPB was not an independent predictor of risk for the occurrence of death in 30 days.

Funding Acknowledgement

Type of funding sources: None. Propensity score adjustment by group30-day outcomes vs CABG technique

Less stringent perioperative glucose control improves outcomes after coronary artery bypass graft in patients with insulin dependent diabetes mellitus

Objective

After coronary artery bypass grafting (CABG), studies testing strict glycemic control did not took into account previous insulin use. Our aim was to evaluate the effect of perioperative (PO) control in patients with NonDM (ND), noninsulin- (NIDDM) and insulin-dependent (IDDM) diabetes submitted to CABG.

Methods

We included CABG patients (2010–2017), stratified by DM presence and type. PO glucose was managed with a standardized protocol (IV insulin targeting a glucose <180 mg/dL. Endpoints included in-hospital death, major adverse cardiac and cerebrovascular (MACCE) events, deep sternal wound infection [DSWI], and major infections. PO glucose control was stratified in 4 quartiles using the highest glucose level: 1st, <140mg/dL; 2nd, 140–179mg/dL; 3rd, 180–239mg/dL; and 4th, >240mg/dL). Multivariable analysis was used to model the association of PO glucose control with outcomes, taking the presence and type of DM into account. All analysis on SPSS 23 (SPSS, IBM, 2018), with p<0.05 as statistically significant.

Results

2020 CABG pts, age 64±10 y, 31% female, DM 37,5% (66% NIDDM, 34% IDDM). Compared with DM, neither NIDDM nor IDDM were associated with mortality (OR=0.99 [0.61–1.61], p=0.985) or MACCE (OR=0.12 [0.81–1.54], p=0.477). In multivariable analysis, DM (OR=1.58 [1.01–2.49], p=0.049) and IDDM (OR=2.55 [1.57–4.16], p<0.001) were independently associated with DSWI. In a mediation analysis, the inclusion of IDDM in the model, weakened the association of DM with DSWI into nonsignificance (OR=1.20 [0.73–1.98], p=0.456), while IDDM retained significant association with DSWI (OR=2.37 [1.39–4.01], p=0.001), indicating that the impact of DM on the incidence of DSWI is fully explained by the IDDM patients. Poor PO glycemic control was an independent predictor of death (OR=1.09, 95% CI 1.04–1.13, p<0.001; 9% higher mortality to each 10mg/dL increase). Accordingly, patients from ND group in the highest stratum of glucose control (4th quartile), compared with the other 3 quartiles, showed increased mortality (3.8%, 2.9%, 4.4%, and 17.9%, p<0.001) and MACCE (8.7%, 8.5%, 14.3%, and 39.3%, p<0.001). However, in IDDM patients, poor PO glycemic control was not an independent predictor of mortality (OR=3.34, 95% CI 0.34–38.23, p=0.347). In fact, strict PO glycemic control in IDDM patients (but not in ND and NIDDM) increased the incidence of DSWI (<140mg/dL, 19.8%, vs >240mg/dL, 8.2%, p=0.015) and other major infections (<140mg/dL, 26.2%, vs >240mg/dL, 12.2%, p=0.048).

Conclusion

After CABG, poor glycemic control is an independent predictor of mortality. However, in IDDM patients, PO hyperglycemia is not associated with mortality, and strict glycemic control increased DSWI, major infections and LOS in these patients. These results suggest that IDDM patients submitted to CABG may benefit from less stringent glycemic targets in PO management.

Funding Acknowledgement

Type of funding source: None

P4735Preoperative frailty is a predictor of worse in-hospital outcomes after coronary artery bypass graft surgery and improves the predictive accuracy of EUROSCORE I and II

Introduction

Although coronary artery bypass grafting (CABG) is the most widely performed cardiovascular procedure in the world and is the standard treatment for complex coronary artery disease, the risk prediction for the procedure has major gaps. In this context, preoperative frailty may have a relevant role in the prediction of surgical risk.

Purpose

Our goal was to evaluate the impact of frailty on in-hospital outcomes after CABG and verify if any other comorbidity enhances the effects of fragility.

Methods

Prospective cohort of patients submitted consecutively to isolated CABG between Jan/2013 and Dec/2017. Frailty was defined as any deficiency in the Katz Index. Of the 1508 patients, 126 (8.4%) were classified as frail. Baseline characteristics and outcomes were compared by univariate analysis. Multivariate regression models were applied for the adjusted analysis of outcomes. The predictive accuracy of the regression models were analyzed using ROC curves. The additional predictive accuracy of the frailty and other risk variables were evaluated by comparing the ROC curves with the DeLong test.

Results

The frail patients presented more advanced age, more comorbidities and the majority were female. Frailty was an independent predictor for in-hospital mortality (OR 5.55, p=0.002) and MACCE (OR 5.60, p=0.001). In addition, by means of an adjusted analysis, we identified that the frailty was associated with a longer time of hospitalization (B 4.61, 95% CI 2.12–7.10, p<0.001). We also identified that preoperative anemia was classified as an independent predictor for hospital mortality and MACCE and improved the effect of frailty on outcomes. In this way, we could verify that when associated with surgical risk scores, frailty and anemia significantly improved the predictive accuracy of EuroScore 1 and EuroScore 2 for in-hospital mortality.

Predictive accuracies

Conclusions

Frailty and preoperative anemia are independent predictors of hospital mortality and MACCE after CABG. Frailty was also a predictor of longer hospitalization time. The association of frailty and anemia with surgical risk scores resulted in a significant improvement in the predictive accuracy of the scores. Frailty screening by Katz Index improved the risk assessment for isolated CABG and, when associated with anemia, demonstrated that frail and anemic patients had worse surgical outcomes.

Acknowledgement/Funding

The development of the present study was funded entirely by the Institution itself.

Evaluation of Tumor Response Using Alpha-fetoprotein and Des-gamma-carboxy Prothrombin in Hepatocellular Carcinoma Patients Who Underwent Transarterial Chemoembolization

Introduction: The aim of the study is to evaluate the role of alpha-fetoprotein (AFP) and des-y-carboxy prothrombin (DCP) in the assessment of treatment response at one month in patients with hepatocellular carcinoma (HCC) treated with trans-arterial chemoembolization (TACE). Methods: From March 2016 to April 2017 a number of 59 patients diagnosed with HCC were prospectively enrolled. A TACE procedure as initial treatment modality was performed in 41 patients. AFP and DCP serum levels were measured and clinical features were determined for all the patients that were included. The Wilcoxon rank test was used to compare variables at baseline and at one month after the procedure. Results: Treatment was performed in 86.4% of the patients diagnosed with HCC, 27 patients received a classical TACE procedure, 14 patients were treated with DEB-TACE, radiofrequency ablation was performed in 3 patients and 4 patients received a liver transplant as initial treatment. Systemic therapy with Sorafenib was started in 3 patients (5%) and in 8 cases no treatment was performed. AFP value significantly decreased at one month in patients that underwent TACE therapy (median value 240.3 vs. 123.7 ng/mL, p=0.020). The same significant decrease was noted for DCP values (median value 1376.8 vs. 769 mAU/mL, p=0.0033). Both AFP (85.5 vs. 18.7 ng/mL, p=0.035) and DCP values (693.2 vs. 58.2 ng/mL, p=0.0003) were significantly lower only in subjects who achieved complete response after TACE and not in patients with partial response. In patients treated with TACE therapy, there was a down-sizing of the maximum diameter of the tumor nodule (30 vs. 27 mm, p=0.02).

CONCLUSION

There was a significant decrease of AFP and DCP values after complete response in HCC patients treated with TACE. DCP is a more effective tumor marker in predicting response than AFP, with no benefit found in their combination.

Predictive Factors of Tumor Recurrence and Survival in Patients with Hepatocellular Carcinoma treated with Transarterial Chemoembolization

BACKGROUND AND AIMS

To evaluate the predictive factors for recurrence of the disease and overall survival (OS) after achieving complete response (CR) in patients with hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE).

METHODS

From January 2013 to December 2017, 168 treatment-naïve patients diagnosed with HCC underwent TACE as a first-line therapy and the gathered data was retrospectively reviewed. We determined the predictive factors for complete response (CR), for recurrence after CR and for survival using the Cox proportional hazard model.

RESULTS

Median follow-up was 27.4 months (range 4-65 months). The mean patient age was 62.2+/-7.9 years. Eighty-three patients had an α-fetoprotein (AFP) level > 20ng/mL. The median maximal diameter of the tumors was 3.5 cm. Sixty-three patients (37.5%) achieved CR after TACE, and recurrence after CR was detected in 37 patients (58.7%). In multivariate analysis, tumor size (</=4.5 cm) and a single tumor were found to be predictive factors for CR, with hazard ratios (HRs) of 2.352 (p=0.022) and 3.964 (p<0.0001), respectively. After achieving CR the median time to recurrence was 12 months (range 6-24 months). Elevated serum AFP > 25 ng/mL and multiple tumors were demonstrated to have a significant relationship with recurrence after CR, with HRs of 1.650 (p=0.05) and 3.932 (p=0.038), respectively. Increased initial serum AFP > 22 ng/mL, tumor size > 4.5 cm, outside Milan criteria, not receiving a liver transplant and presence of portal vein thrombosis (PVT) were correlated with poor survival.

CONCLUSIONS

In patients treated with TACE as an initial therapy, tumor size (≤4.5 cm) and single tumor were predictive factors for CR. Multiple nodules and an elevated serum AFP > 25 ng/mL were predictive factors for recurrence after CR. Outside Milan criteria tumors, elevated AFP levels and the presence of PVT were significantly correlated with decreased survival.

The Role of Beta-7 Integrin and Carbonic Anhydrase IX in Predicting the Occurrence of de Novo Nonalcoholic Fatty Liver Disease in Liver Transplant Recipients

Background: Liver transplant (LT) recipients are at increased risk for developing metabolic syndrome. Early detection of NAFLD and other components of the metabolic syndrome is an important step in reducing morbidity and mortality. Methods: We assessed 60 liver transplant recipients for clinical and biological features, performed abdominal ultrasound and transient elastography (TE) Fibroscan© with controlled attenuation parameter (CAP), calculated non-invasive scoring systems APRI, FIB-4, NAFLD score, cardiovascular risk (Framingham risk score) and for the presence of metabolic syndrome and performed two biomarkers: beta 7 integrin and carbonic anhydrase IX. Results: Sixty liver transplant recipients underwent clinical and biochemical evaluation, abdominal ultrasound and TE with CAP. The median age was 56.5 years and the median time from transplantation 35 months. The Spearman correlation coefficient of beta 7 integrin and the liver stiffness measurement values obtained via Fibroscan© we obtained a moderate correlation r=0.31, but a significant association (p=0.01). The univariate analysis showed significant association between both biomarkers and liver fibrosis assessed with a cut-off value of advanced fibrosis of 8.7 kPa. The carbonic anhydrase IX showed a better correlation when compared to the liver stiffness with a correlation coefficient of 0.43 and p-value=0.0007 and a moderate correlation when compared to both FIB-4 (r=0.27) and APRI (r=0.27) score for liver fibrosis but with a significant p value=0.04, respectively 0.03.

CONCLUSION

We consider very important for our patients the development of new non-invasive biomarkers for early diagnosis of NAFLD and NASH, as the "gold-standard" of liver biopsy is not easily accepted in clinical practice. Also NAFLD and NASH are dynamic processes that need prospective and repeated assessments, a need that cannot be met by the classical liver biopsy.

[Synchronous gastrointestinal stromal tumor (GIST) and multiple digestive neoplasms, benign and malignant]

Gastrointestinal stromal tumors (GIST) are a broad category of mesenchymal, non-epithelial primary tumors of the digestive tract, located in the wall of hollow viscera, from the esophagus to the anus and often in adjacent mesentery and omentum. They are clinically unpredictable (may be discovered incidentally during an imagistic investigation or during surgery for other pathological entity, or at necropsy) and also have an unpredictable behavior (GISTs with very low risk, with low or moderate malignancy, which have benign histopathologic features but can recurr or can metastasize). The case we present here represents a rare association between a synchronous gastrointestinal stromal tumor (GIST) and multiple gastric benign and malignant tumors.

[Adenoid cystic carcinoma of the breast--two case reports]

Adenoid cystic carcinoma is a rare type of breast carcinoma with a good prognosis. It represents less than 0,1% of breast carcinomas. We present two cases of adenoid cystic carcinoma diagnosed in the Surgical Department of Coltea Hospital in the last 3 years. The first case is a 66 years old patient with a breast tumor that has clinical and imagistic features compatible with a benign diagnosis. The frozen sections established the diagnosis of adenoid cystic carcinoma, confirmed by histopathologic examination of paraffin embedded tissue and immunohistochemistry. The second case is a 68 years old patient with a breast tumor located in the central quadrant of the left breast, with skin infiltration. Preoperatory fine needle aspiration is sugestive of a papillary tumor, so the cytologic exam cannot establish malignancy. The frozen sections established the diagnosis of ductal invasive carcinoma and histopathologic examination of paraffin embedded tissue and immunohistochemistry established the diagnosis of adenoid cystic carcinoma associated with ductal invasive carcinoma grade I and adenomyoepitelioma. The cytology had a false papillary aspect, in fact there was amorphous material contained in pseudoluminal spaces. In both cases the treatment was surgical resection with tumor excision and free resection margins. In the second case lymphadenectomy was also performed.

T and B lymphocyte depletion has a marked effect on the fibrosis of dystrophic skeletal muscles in the scid/mdx mouse

Abnormal connective tissue proliferation following muscle degeneration is a major pathological feature of Duchenne muscular dystrophy (DMD), a genetic myopathy due to lack of the sarcolemmal dystrophin protein. Since this fibrotic proliferation is likely to be a major obstacle to the efficacy of future therapies, research is needed to understand and prevent the fibrotic process in order to develop an effective treatment. Murine muscular dystrophy (mdx) is genetically homologous to DMD, and histopatological alterations are comparable to those of the muscles of patients with DMD. To investigate the development of fibrosis, we bred the mdx mouse with the scid immunodepressed mouse and analysed fibrosis histologically; we used ELISA analysis to determine TGF-beta1 expression. Significant reduction of fibrosis and TGF-beta1 expression was found in the muscles of the scid/mdx mice. However, we observed similar centrally located nuclei, necrosis, muscle degeneration and muscle force compared to the mdx animals. These data demonstrate a correlation between the absence of B and T lymphocytes and loss of fibrosis accompanied by reduction of TGF-beta1, suggesting the importance of modulation of the immune system in DMD.

A BioSpi model of lymphocyte-endothelial interactions in inflamed brain venules

This paper presents a stochastic model of the lymphocyte recruitment in inflammed brain microvessels. The framework used is based on stochastic process algebras for mobile systems. The automatic tool used in the simulation is the BioSpi. We compare our approach with classical hydrodinamical specifications.

Chemokines trigger immediate beta2 integrin affinity and mobility changes: differential regulation and roles in lymphocyte arrest under flow

Chemokines trigger rapid integrin-dependent lymphocyte arrest to vascular endothelium. We show that the chemokines SLC, ELC, and SDF-1alpha rapidly induce lateral mobility and transient increase of affinity of the beta2 integrin LFA-1. Inhibition of phosphatidylinositol 3-OH kinase (PI(3)K) activity blocks mobility but not affinity changes and prevents lymphocyte adhesion to ICAM-1 immobilized at low but not high densities, suggesting that mobility enhances the frequency of encounters between high-affinity integrin and ligand but that at higher ligand density affinity changes are sufficient for arrest. Thus, chemokines trigger, through distinct signaling pathways, both a high-affinity state and lateral mobility of LFA-1 that can coordinately determine the vascular arrest of circulating lymphocytes under physiologic conditions.

Induction of adhesion molecules on human schwann cells by proinflammatory cytokines, an immunofluorescence study

The presence of cytokines in the peripheral nerve was positively correlated to the induction and progression of inflammation during experimental allergic neuritis (EAN) and Guillain Barré syndrome (GBS). We investigated the induction of adhesion molecules such as L-selectin, E-selectin, ICAM-1, VCAM-1 and Mac-1 on Schwann cells by proinflammatory cytokines. Cultured human Schwann cells from normal adult, fetal and diabetic nerves were studied by immunofluorescence at basal condition and after stimulation with cytokines for 6, 24, 48 and 96 h. Incubation of human Schwann cells with TNFalpha, IFNgamma and IL-1beta induces the expression of ICAM-1 starting at 6 h and reaching a peak at 24 h on more than 90% of cells. VCAM-1 expression was induced after 6 h of treatment with TNFalpha and IL-1beta on almost 100% of Schwann cells. Surprisingly, stimulation with TNFalpha, IFNgamma and IL-1beta also induced the expression of L-selectin on fetal and diabetic Schwann cells, but not on normal adult cells. E-selectin, an adhesion molecule classically upregulated during inflammation, as well as Mac-1, a ligand for ICAM-1, were not expressed on human Schwann cells at basal condition or after treatment with cytokines. No ICAM-1, VCAM-1 and L-selectin expression was found on unstimulated Schwann cells. Our results suggest that upregulation of adhesion molecules on Schwann cells may have a role in the pathogenesis of inflammation in the peripheral nerve.

Inhibition of experimental autoimmune encephalomyelitis by a tyrosine kinase inhibitor

Migration of lymphocytes from the blood into the brain is a critical event in the pathogenesis of experimental autoimmune encephalomyelitis. Lymphocyte adhesion to brain endothelium is the first step in lymphocyte entry into the central nervous system, leading subsequently to myelin damage and paralysis. In this paper we show that the tyrosine kinase inhibitor, tyrphostin AG490, prevents binding of freshly isolated mouse lymph node cells and of in vivo activated lymphocytes to endothelium of inflamed brain in Stamper-Woodruff adhesion assays. Moreover, AG490 inhibits adhesion of encephalitogenic T cell lines to purified ICAM-1 and VCAM-1, molecules implicated in T cell recruitment into the central nervous system. In contrast, 2-h treatment of T cell lines with high doses of tyrphostin AG490 have no effect on the viability, intracellular calcium elevation induced by Con A or TCR cross-linking, proliferation, or TNF production by Ag-stimulated T cell lines. Systemic administration of AG490 prevents the accumulation of leukocytes in the brain and the development of experimental autoimmune encephalomyelitis induced by proteolipid protein, peptide 139-151-specific T cell lines in SJL/J mice. Blood leukocytes isolated from mice treated with tyrphostin AG490 are less adhesive on purified very late Ag-4 ligands compared with adhesion of leukocytes from control animals. Our results suggest that inhibition of signaling pathways involved in lymphocyte adhesion may represent a novel therapeutic approach for demyelinating diseases.

Tyrphostin AG490, a tyrosine kinase inhibitor, blocks actively induced experimental autoimmune encephalomyelitis

Migration of lymphocytes from blood into the brain is a critical event in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Previous observations made in our laboratory showed that protein tyrosine kinase inhibitors were able to block lymphocyte adhesion to brain endothelium and prevent the entry of encephalitogenic T cell lines into the brain of SJL/J mice. Here we show that systemic administration of the protein tyrosine kinase inhibitor, tyrphostin AG490, blocks the development of actively induced EAE in a dose-dependent manner. Administration of 1 mg of drug daily significantly decreased the severity of the disease, while 3 mg of AG490 daily totally blocked the disease in 62% of treated animals, and in those that developed the disease, paralysis was delayed and clinical score was significantly reduced. Blood leukocytes isolated from mice treated with tyrphostin AG490 were less adhesive on VCAM-1 and fibronectin, when compared with control animals. AG490 treatment had no effect on the proliferation by antigen-stimulated peripheral lymph nodes cells. Interestingly, cells obtained from draining lymph nodes in AG490-treated animals and stimulated with antigen secreted two times more IFN-gamma and four times more IL-10, when compared with control animals, whereas no difference was observed in TNF-alpha production. Our results suggest that tyrphostin AG490 may have therapeutic potential by blocking tyrosine kinase activities involved in key mechanisms leading to demyelinating diseases of the central nervous system.

Evidence of zeta protein kinase C involvement in polymorphonuclear neutrophil integrin-dependent adhesion and chemotaxis

Classical chemoattractants and chemokines trigger integrin-dependent adhesion of blood leukocytes to vascular endothelium and also direct subsequent extravasation and migration into tissues. In studies of human polymorphonuclear neutrophil responses to formyl peptides and to interleukin 8, we show evidence of involvement of the atypical zeta protein kinase C in the signaling pathway leading to chemoattractant-triggered actin assembly, integrin-dependent adhesion, and chemotaxis. Selective inhibitors of classical and novel protein kinase C isozymes do not prevent chemoattractant-induced neutrophil adhesion and chemotaxis. In contrast, chelerythrine chloride and synthetic myristoylated peptides with sequences based on the endogenous zeta protein kinase C pseudosubstrate region block agonist-induced adhesion to fibrinogen, chemotaxis and F-actin accumulation. Biochemical analysis shows that chemoattractants trigger rapid translocation of zeta protein kinase C to the plasma membrane accompanied by rapid but transient increase of the kinase activity. Moreover, pretreatment with C3 transferase, a specific inhibitor of Rho small GTPases, blocks zeta but not alpha protein kinase C plasma membrane translocation. Synthetic peptides from zeta protein kinase C also inhibit phorbol ester-induced integrin-dependent adhesion but not NADPH-oxidase activation, and C3 transferase pretreatment blocks phorbol ester-triggered translocation of zeta but not alpha protein kinase C. These data suggest the involvement of zeta protein kinase C in chemoattractant-induced leukocyte integrin-dependent adhesion and chemotaxis. Moreover, they highlight a potential link between atypical protein kinase C isozymes and Rho signaling pathways leading to integrin-activation.

Tyrphostin AG490, a tyrosine kinase inhibitor, blocks actively induced experimental autoimmune encephalomyelitis

Migration of lymphocytes from blood into the brain is a critical event in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Previous observations made in our laboratory showed that protein tyrosine kinase inhibitors were able to block lymphocyte adhesion to brain endothelium and prevent the entry of encephalitogenic T cell lines into the brain of SJL/J mice. Here we show that systemic administration of the protein tyrosine kinase inhibitor, tyrphostin AG490, blocks the development of actively induced EAE in a dose-dependent manner. Administration of 1 mg of drug daily significantly decreased the severity of the disease, while 3 mg of AG490 daily totally blocked the disease in 62% of treated animals, and in those that developed the disease, paralysis was delayed and clinical score was significantly reduced. Blood leukocytes isolated from mice treated with tyrphostin AG490 were less adhesive on VCAM-1 and fibronectin, when compared with control animals. AG490 treatment had no effect on the proliferation by antigen-stimulated peripheral lymph nodes cells. Interestingly, cells obtained from draining lymph nodes in AG490-treated animals and stimulated with antigen secreted two times more IFN-gamma and four times more IL-10, when compared with control animals, whereas no difference was observed in TNF-alpha production. Our results suggest that tyrphostin AG490 may have therapeutic potential by blocking tyrosine kinase activities involved in key mechanisms leading to demyelinating diseases of the central nervous system.

Cultured human monocytes release proinflammatory cytokines in response to myelin basic protein

In human cultured monocytes we examined the ability of myelin basic protein (MBP) to induce the production of proinflammatory cytokines potentially involved in inflammatory demyelination. Northern blots and specific immunoassays demonstrated that monocytes incubated with optimal doses of MBP showed increased mRNA expression and release of tumor necrosis factor (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8) but not of interleukin-12/p40 (IL-12/p40). We also showed that cytokine production by MBP-stimulated monocytes was abrogated by incubation with Dexamethasone. These data suggest that interaction of mononuclear phagocytes with MBP may participate in the regulatory process of cytokine production during inflammatory demyelination and support the beneficial role of corticosteroids therapy in aberrant immune responses to the myelin sheath.

Novel method for following lymphocyte traffic in mice using [3H]glycerol labeling

We describe a new method based on radioactive metabolic labeling with [3H]glycerol to study the lymphocyte trafficking in mice. Lymphocyte labeling with [3H]glycerol is time- and dose-dependent. Radioactive leaking is less significant than in 51Cr-labeled cells. Lymphocytes, labeled with [3H]glycerol, with 51Cr, or with both labels together show the same pattern of homing to Peyer's patches (PP), peripheral and mesenteric lymph nodes and spleen and homing shows the expected dependence on pertussis toxin (PTX)-sensitive signaling, suggesting that the labeling procedure with [3H]glycerol does not affect lymphocyte trafficking properties. Tissue accumulation can be readily assessed by scintillation counting of sonicated samples obtained after perfusion of the vasculature with saline to remove blood. Moreover, we show that cell labeling with [3H]glycerol provides improved sensitivity in assessing the accumulation of small numbers of labeled cells in non-lymphoid organs, and permits identification of homed leukocytes in histologic sections.

Sulfatides trigger cytokine gene expression and secretion in human monocytes

We investigated whether sulfatides are able to trigger transmembrane signals and activation of selective cell functions in human monocytes. Sulfatides stimulated an increase in cytosolic free-calcium in monocytes, and this depended on the release of calcium from intracellular stores. Non-sulfated galactocerebrosides had no effect on monocyte cytosolic free calcium. Sulfatides enhanced expression of tumor necrosis factor, interleukin-8, and interleukin-1 beta, but not interleukin-12/natural killer cell stimulating factor mRNAs. Sulfatides also triggered secretion of cytokines into the extracellular medium, although they were much less effective than lipopolysaccharide. Both enhanced expression of cytokine mRNAs and secretion by sulfatides required sulfation of the galactose ring of the glycolipid as non-sulfated galactocerebrosides had no effect. These findings suggest that sulfatides that are released at sites of inflammation can amplify the inflammatory reaction triggering cytokine expression in, and release by, monocytes.

Sulfatides trigger increase of cytosolic free calcium and enhanced expression of tumor necrosis factor-alpha and interleukin-8 mRNA in human neutrophils. Evidence for a role of L-selectin as a signaling molecule

Sulfatides have been established recently as ligands for L-selectin, and we investigated whether they trigger transmembrane signals through ligation of L-selectin. We found that sulfatides trigger the increase of cytosolic free calcium in neutrophils and that this effect was strictly dependent on sulfation of the galactose ring, as non-sulfated galactocerebrosides were not stimulatory. Chymotrypsin and phorbol 12-myristate 13-acetate treatment of neutrophils caused shedding of L-selectin, but not of class I major histocompatibility complex antigens or beta 2 integrins, and blunted the capability of neutrophils to respond to sulfatides with an increase of cytosolic free calcium. Four different anti-L-selectin antibodies (DREG-200, LAM1/3, LAM1/6, and LAM1/10), but not four control antibodies directed against different surface molecules of neutrophils, also triggered an increase of cytosolic free calcium. The anti-L-selectin antibodies were stimulatory both if used in a soluble form, after cross-linking with anti-mouse F(ab')2 fragments, and immobilized to protein A of Staphylococcus aureus through the Fc fragment. With immobilized antibodies, an increase of cytosolic free calcium was found also by plating neutrophils on antibodies bound to protein A-coated coverslips and monitoring the increase of cytosolic free calcium by fluorescence microscopy. Both sulfatides and anti-L-selectin antibody effects were not inhibited by pertussis toxin, thus indicating that a pertussis toxin-sensitive GTP-binding protein was not involved in signal transduction. Sulfatides also triggered an increase of tumor necrosis factor-alpha and interleukin-8 mRNAs in neutrophils. Also to act as stimuli of cytokine mRNA expression, sulfatides required sulfation of the galactose ring, as non-sulfated galactocerebrosides were not stimulatory, and depended on expression of L-selectin, as shedding of this molecules induced by chymotrypsin blunted their effects. These findings suggest that L-selectin can transduce signals activating selective cell function.

Interleukin 10 (IL-10) inhibits the release of proinflammatory cytokines from human polymorphonuclear leukocytes. Evidence for an autocrine role of tumor necrosis factor and IL-1 beta in mediating the production of IL-8 triggered by lipopolysaccharide

In this study we have examined the effects of interleukin 10 (IL-10) on polymorphonuclear leukocytes (PMN), and found that it is a potent inhibitor of tumor necrosis factor (TNF), IL-1 beta, and IL-8 secretion triggered by lipopolysaccharide (LPS). Cytokine production by phagocytosing PMN was also inhibited by IL-10, but to a lesser extent than the LPS-induced production. As shown by Northern blot analysis, IL-10 diminished the levels of TNF, IL-1 beta, and IL-8 mRNAs late after the onset of stimulation of PMN with LPS. In addition, we provide evidence that the kinetics of LPS-induced IL-8 production by PMN is composed of two distinct phases. Specifically, our experiments demonstrated that in the first phase, the production of IL-8 is a process directly induced by LPS that lasts for some hours. After this early wave, a second phase begins that is sustained and leads to an elevated production of IL-8 that appears to be due to the endogenous release of TNF and IL-1 beta. This second wave can in fact be blocked by anti-TNF and anti-IL-1 beta neutralizing antibodies, and by IL-10 as the consequence of its downregulatory effects on TNF and IL-1 beta release. Taken together, these findings identify novel biological actions of IL-10 as a suppressor of the inflammatory response.

Production of tumor necrosis factor and other proinflammatory cytokines by human mononuclear phagocytes stimulated with myelin P2 protein

In this study we examined the effect of myelin P2 protein on some proinflammatory functions exerted by human mononuclear phagocytes. Northern blot analysis demonstrated that P2 protein selectively induced in monocytes and macrophages mRNA accumulation of tumor necrosis factor (TNF), interleukin 1 beta (IL-1 beta), and interleukin 8 (IL-8) in a time-dependent manner. Natural killer stimulating factor (IL-12) mRNA and protein secretion was strongly induced by lipopolysaccharide but not by P2 protein. Supernatants harvested from P2-stimulated monocytes contained significant amounts of TNF, IL-1 beta, and IL-8, whereas those from macrophages contained only TNF and IL-8. The effect of the P2 protein on TNF and IL-8 mRNA accumulation and secretion was not affected by polymyxin B, which, on the other hand, almost completely abolished the effect of lipopolysaccharide. Finally, P2 protein did not directly trigger hydrogen peroxide release but, through the induced release of TNF, potentiated monocyte respiratory burst capability. Since P2 protein is the antigen responsible for the induction of experimental allergic neuritis, these findings identify a potential mechanism involved in the inflammatory reaction and myelin damage during experimental allergic neuritis.

Studies on the regulatory mechanisms of interleukin-8 gene expression in resting and IFN-gamma-treated neutrophils: evidence on the capability of staurosporine of inducing the production of interleukin-8 by human neutrophils

To understand how expression of IL-8 mRNA is regulated, we studied the effects of Staurosporine, H7, phorbol-myristate-acetate and Dexamethasone in human neutrophils subsequently treated with IFN-gamma. Our results can be summarized as follows: a) IL-8 mRNA steady state levels were enhanced in a dose dependent fashion by both Staurosporine and phorbol-myristate-acetate, were not influenced by H7, but were decreased by Dexamethasone; b) the negative effect of IFN-gamma on IL-8 mRNA accumulation was prevented by Staurosporine and phorbol-myristate-acetate, was not influenced by H7, and was potentiated by Dexamethasone; c) IL-8 mRNA induction caused by Staurosporine was accompanied by a time and dose dependent release of IL-8 into the PMN supernatants.