Increased plasma levels of Gas6 and its soluble tyrosine kinase receptors Mer and Axl are associated with immunological activity and severity of lupus nephritis.

OBJECTIVES: Growth arrest-specific 6 (Gas6) and its receptors have been shown to play a crucial role in the homeostasis of the innate immune system by regulating apoptosis and inflammation. We aimed to verify whether an impairment of this system is associated with systemic lupus erythematosus (SLE) disease activity and with lupus nephritis (LN). METHODS: Plasma Gas6 and the soluble cleaved form of the receptors MerTK (sMer) and Axl (sAxl) concentrations were measured in n=59 SLE patients (n=44 with nephritis, 75%) and analysed in relationship to clinical and laboratory data. RESULTS: Patients with LN were characterised by higher Gas6 (19.0 ng/mL [16.8-24.5] vs. 16.5 ng/mL [13.89-18.91]; p=0.03) and sAxl plasma levels than those without LN (31.36 ng/mL [25.1-41.4] vs. 20.2 ng/mL [15.6-30.7]; p=0.03); conversely sMer plasma concentrations were similar between groups. All the three biomarkers studied were directly correlated to creatinine and daily proteinuria, being inversely related to creatinine clearance. 39 patients had a proteinuria level of <0.5 mg/day, 14 between 0.5 and 3.5 mg/day and 5 had ≥3.5 g/day; Gas6, sAxl and sMer plasma concentrations significantly increased for increasing degree of proteinuria (test for trend p=0.0002; p=0.02; p=0.009, respectively).These correlations were confirmed in multiple linear regression analysis models accounting for gender, age, disease duration and concomitant treatment. CONCLUSIONS: Plasma Gas6, sAxl and sMer concentrations are associated with the severity of LN in patients affected by SLE. The excess cleavage of TAM receptors might contribute to LN pathogenesis.

Osteopontin at the Crossroads of Inflammation and Tumor Progression.

Complex interactions between tumor and host cells regulate systemic tumor dissemination, a process that begins early at the primary tumor site and goes on until tumor cells detach themselves from the tumor mass and start migrating into the blood or lymphatic vessels. Metastatic cells colonize the target organs and are capable of surviving and growing at distant sites. In this context, osteopontin (OPN) appears to be a key determinant of the crosstalk between cancer cells and the host microenvironment, which in turn modulates immune evasion. OPN is overexpressed in several human carcinomas and has been implicated in inflammation, tumor progression, and metastasis. Thus, it represents one of the most attracting targets for cancer therapy. Within the tumor mass, OPN is secreted in various forms either by the tumor itself or by stroma cells, and it can exert either pro- or antitumorigenic effects according to the cell type and tumor microenvironment. Thus, targeting OPN for therapeutic purposes needs to take into account the heterogeneous functions of the multiple OPN forms with regard to cancer formation and progression. In this review, we will describe the role of systemic, tumor-derived, and stroma-derived OPN, highlighting its pivotal role at the crossroads of inflammation and tumor progression.

Are Baseline Levels of Gas6 and Soluble Mer Predictors of Mortality and Organ Damage in Patients with Sepsis? The Need-Speed Trial Database.

Soluble tyrosine kinase receptor Mer (sMer) and its ligand Growth arrest-specific protein 6 (Gas6) are predictors of mortality in patients with sepsis. Our aim is to clarify whether their measurement at emergency department (ED) presentation is useful in risk stratification. We re-analyzed data from the Need-Speed trial, evaluating mortality and the presence of organ damage according to baseline levels of sMer and Gas6. 890 patients were eligible; no association with 7- and 30-day mortality was observed for both biomarkers (p > 0.05). sMer and Gas6 levels were significantly higher in acute kidney injury (AKI) patients compared to non-AKI ones (9.8 [4.1-17.8] vs. 7.9 [3.8-12.9] ng/mL and 34.8 [26.4-47.5] vs. 29.8 [22.1-41.6] ng/mL, respectively, for sMer and Gas6), and Gas6 also emerged as an independent AKI predictor (odds ratio (OR) 1.01 [1.00-1.02]). Both sMer and Gas6 independently predicted thrombocytopenia in sepsis patients not treated with anticoagulants (OR 1.01 [1.00-1.02] and 1.04 [1.02-1.06], respectively). Moreover, sMer was an independent predictor of both prothrombin time-international normalized ratio (PT-INR) > 1.4 (OR 1.03 [1.00-1.05]) and sepsis-induced coagulopathy (SIC) (OR 1.05 [1.02-1.07]). An early measurement of the sMer and Gas6 plasma concentration could not predict mortality. However, the biomarkers were associated with AKI, thrombocytopenia, PT-INR derangement and SIC, suggesting a role in predicting sepsis-related organ damage.

Growth Arrest-Specific Gene 6 Administration Ameliorates Sepsis-Induced Organ Damage in Mice and Reduces ROS Formation In Vitro.

Sepsis is a widespread life-threatening disease, with a high mortality rate due to inflammation-induced multiorgan failure (MOF). Thus, new effective modulators of the immune response are urgently needed to ameliorate the outcome of septic patients. As growth arrest-specific gene 6 (Gas6)/Tyro3, Axl, MerTK (TAM) receptors signaling has shown immunomodulatory activity in sepsis, here we sought to determine whether Gas6 protein injection could mitigate MOF in a cecal slurry mouse model of sepsis. Mice, divided into different groups according to treatment-i.e., placebo (B), ampicillin (BA), Gas6 alone (BG), and ampicillin plus Gas6 (BAG)-were assessed for vitality, histopathology and cytokine expression profile as well as inducible nitric oxide synthase (iNOS), ALT and LDH levels. BAG-treated mice displayed milder kidney and lung damage and reduced levels of cytokine expression and iNOS in the lungs compared to BA-treated mice. Notably, BAG-treated mice showed lower LDH levels compared to controls. Lastly, BAG-treated cells of dendritic, endothelial or monocytic origin displayed reduced ROS formation and increased cell viability, with a marked upregulation of mitochondrial activity. Altogether, our findings indicate that combined treatment with Gas6 and antibiotics ameliorates sepsis-induced organ damage and reduces systemic LDH levels in mice, suggesting that Gas6 intravenous injection may be a viable therapeutic option in sepsis.

Finding the seed of recurrence: Hepatocellular carcinoma circulating tumor cells and their potential to drive the surgical treatment.

The treatment for hepatocellular carcinoma (HCC) relies on liver resection, which is, however, burdened by a high rate of recurrence after surgery, up to 60% at 5 years. No pre-operative tools are currently available to assess the recurrence risk tailored to every single patient. Recently liquid biopsy has shown interesting results in diagnosis, prognosis and treatment allocation strategies in other types of cancers, since its ability to identify circulating tumor cells (CTCs) derived from the primary tumor. Those cells were advocated to be responsible for the majority of cases of recurrence and cancer-related deaths for HCC. In fact, after being modified by the epithelial-mesenchymal transition, CTCs circulate as "seeds" in peripheral blood, then reach the target organ as dormant cells which could be subsequently "awakened" and activated, and then initiate metastasis. Their presence may justify the disagreement registered in terms of efficacy of anatomic vs non-anatomic resections, particularly in the case of microvascular invasion, which has been recently pointed as a histological sign of the spread of those cells. Thus, their presence, also in the early stages, may justify the recurrence event also in the contest of liver transplant. Understanding the mechanism behind the tumor progression may allow improving the treatment selection according to the biological patient-based characteristics. Moreover, it may drive the development of novel biological tailored tests which could address a specific patient to neoadjuvant or adjuvant strategies, and in perspective, it could also become a new method to allocate organs for transplantation, according to the risk of relapse after liver transplant. The present paper will describe the most recent evidence on the role of CTCs in determining the relapse of HCC, highlighting their potential clinical implication as novel tumor behavior biomarkers able to influence the surgical choice.

Hypernatremia and moderate-to-severe hyponatremia are independent predictors of mortality in septic patients at emergency department presentation: A sub-group analysis of the need-speed trial.

STUDY OBJECTIVE: Early risk stratification of septic patients presenting to the emergency department (ED) is challenging. The aim of the study was to evaluate the prognostic role of plasmatic sodium level (PNa+) derangements at ED presentation in septic patients. METHODS: According to PNa+ at ED presentation patients were divided in eunatremic (136-145 mEq/L), hypernatremic (>145 mEq/L) and hyponatremic (<136 mEq/L). Hyponatremic patients were subsequently divided in mild (130-135 mEq/L), moderate (125-129 mEq/L) and severe (<125 mEq/L). 7 and 30-day mortality was evaluated according to PNa+ derangements and the degree of hyponatremia. The same analysis was then performed only in respiratory tract infection-related (RTI-r) sepsis patients. RESULTS: 879 septic patients were included in this analysis, 40.3% had hyponatremia, 5.7% hypernatremia. Hypernatremia showed higher mortality rates at both endpoints compared to eunatremia and hyponatremia (p<0.0001 for both). Eunatremia and mild hyponatremia were compared vs. moderate-to-severe hyponatremia showing a significant difference in terms of 7 and 30-day survival (p = 0.004 and p = 0.007, respectively). The Cox proportional model identified as independent predictors of 7 and 30-day mortality moderate-to-severe hyponatremia (HR 4.89[2.38-10.03] and 1.79[1.07-3.01], respectively) and hypernatremia (HR 3.52[1.58-7.82] and 2.14[1.17-3.92], respectively). The same analysis was performed in patients with respiratory tract infection-related sepsis (n = 549), with similar results. CONCLUSION: Both hypernatremia and moderate-to-severe hyponatremia at ED presentation independently predict mortality in septic patients, allowing early risk stratification and suggesting more aggressive therapeutic strategies.

Interferon signature in immunosuppressed patients with lower respiratory tract infections: dosage on bronchoalveolar lavage.

BACKGROUND: Interferon signature (IS) is the measure of transcripts belonging to pathways of interferon activation. Viral infections can interfere with the interferon pathway, in particular herpesvirus present in immunocompromised hosts. The aim of our study was to evaluate if herpesvirus infections in immunocompromised patients with lower respiratory tract infections (LRTI) could lead to IS alterations. METHODS: We measured IS transcription of six genes on bronchoalveolar lavage of immunocompromised patients with LRTI (IFI27, IFI44, IFIT1, ISG15, RSAD2, SIGLEC1). Patients were divided in three groups based on Epstein-Barr virus (EBV) and other herpesviruses coinfections. RESULTS: We included 56 patients, 10 without and 17 with only EBV reactivation (respectively N and E groups) and 29 with EBV and other herpesviruses (group C). IS was higher in group C (P=0.01) compared to other ones, but single gene expressions were different among groups: IFI27 was higher whereas IFIT1 and ISG15 were lower in group C (P<0.05). CONCLUSIONS: The continuous stimulation of interferon cascade by herpesviruses enhances IS. The analysis of IS in immunocompromised population is possible by limiting the use of IFI27, IFIT1, ISG15 genes. Our preliminary results seem to indicate that IS is a useful biomarker of cellular response to herpesvirus infection in immunocompromised patients.

Role of Gas6 and TAM Receptors in the Identification of Cardiopulmonary Involvement in Systemic Sclerosis and Scleroderma Spectrum Disorders.

BACKGROUND: Few biomarkers are available for early identification of pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) in systemic sclerosis (SS) and scleroderma spectrum disorders (SSD). AIMS: To evaluate Gas6, sAxl, and sMer as biomarkers for cardiopulmonary complications of SS and SSD. METHODS: In a cross-sectional observational study, we recruited 125 consecutive patients, affected by SS and SSD and referred to a tertiary-level pulmonary hypertension outpatient clinic. All patients underwent a comprehensive evaluation for identification of PAH and ILD. Gas6, sMer, and sAxl concentrations were measured with ELISA protocols, and concentrations were compared according to PAH or ILD. RESULTS: Nineteen subjects had pulmonary hypertension (PH) (14 PAH), and 39 had ILD (6 severe). Plasma sMer was increased in PAH (18.6 ng/ml IQR [11.7-20.3]) with respect to the absence (12.4 [8.0-15.8]) or other form of pulmonary hypertension (9.6 [7.4-12.5]; K-W variance p < 0.04). Conversely, Gas6 and sAxl levels were slightly increased in mild ILD (25.8 ng/ml [19.5-32.1] and 24.6 [20.1-32.5]) and reduced in severe ILD (16.6 [15.0-22.1] and 15.5 [14.9-22.4]) in comparison to no evidence of ILD (23.4 [18.8-28.1] and 21.6 [18.1-28.4]; K-W, p ≤ 0.05). Plasma sMer ≥ 19 ng/ml has 50% sensitivity and 92% specificity in PAH identification (area under the ROC curve (AUC) 0.697, p < 0.03). Values of Gas6 ≤ 24.5 ng/ml and of sAxl ≤ 15.5 ng/ml have 100% and 67% sensitivity and 47% and 86% specificity, respectively, in identifying severe ILD (Gas6 AUC 0.787, p < 0.001; sAxl AUC 0.705, p < 0.05). CONCLUSIONS: The assay of Gas6 sAxl and sMer may be useful to help in the identification of PAH and ILD in SS and SSD patients. The Gas6/TAM system seems to be relevant in cardiopulmonary complications of SS and SSD and merits further investigations.

Gas6/TAM Axis in Sepsis: Time to Consider Its Potential Role as a Therapeutic Target.

Tyrosine kinase receptors are transmembrane proteins involved in cell signaling and interaction. Among them, the TAM family (composed by Tyro 3, Axl, and Mer) represents a peculiar subgroup with an important role in many physiological and pathological conditions. Despite different mechanisms of activation (e.g., protein S and Galactin-3), TAM action is tightly related to their common ligand, a protein named growth arrest-specific 6 (Gas6). Since the expression of both TAM and Gas6 is widely distributed among tissues, any alteration of one of these components can lead to different pathological conditions. Moreover, as they are indispensable for homeostasis maintenance, in recent years a growing interest has emerged regarding their role in the regulation of the inflammatory process. Due to this involvement, many authors have demonstrated the pivotal role of the Gas6/TAM axis in both sepsis and the sepsis-related inflammatory responses. In this narrative review, we highlight the current knowledge as well as the last discoveries on TAM and Gas6 implication in different clinical conditions, notably in sepsis and septic shock. Lastly, we underline not only the feasible use of Gas6 as a diagnostic and prognostic biomarker in certain systemic acute conditions but also its potential therapeutic role in these life-threatening diseases.

Severity of Nonalcoholic Fatty Liver Disease in Type 2 Diabetes Mellitus: Relationship between Nongenetic Factors and PNPLA3/HSD17B13 Polymorphisms.

BACKGROUND: The prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM) is high, though its severity is often underestimated. Our aim is to provide an estimate of the prevalence of severe NAFLD in T2DM and identify its major predictors. METHODS: T2DM patients (n=328) not previously known to have NAFLD underwent clinical assessment, transient elastography with measure of liver stiffness (LS) and controlled attenuation parameter (CAP), and genotyping for patatin like phospholipase domain containing 3 (PNPLA3) and 17ß-hydroxysteroid-dehydrogenase type 13 (HSD17B13). RESULTS: Median LS was 6.1 kPa (4.9 to 8.6). More than one-fourth patients had advanced liver disease, defined as LS ≥7.9 kPa (n=94/238, 29%), and had a higher body mass index (BMI) than those with a LS <7.9 kPa. Carriage of the G allele in the PNPLA3 gene was associated with higher LS, being 5.9 kPa (4.7 to 7.7) in C/C homozygotes, 6.1 kPa (5.2 to 8.7) in C/G heterozygotes, and 6.8 kPa (5.8 to 9.2) in G/G homozygotes (P=0.01). This trend was absent in patients with ≥1 mutated HSD17B13 allele. In a multiple linear regression model, BMI and PNPLA3 genotype predicted LS, while age, gender, disease duration, and glycosylated hemoglobin did not fit into the model. None of these variables was confirmed to be predictive among carriers of at least one HSD17B13 mutated allele. There was no association between CAP and polymorphisms of PNPLA3 or HSD17B13. CONCLUSION: Advanced NAFLD is common among T2DM patients. LS is predicted by both BMI and PNPLA3 polymorphism, the effect of the latter being modulated by mutated HSD17B13.

The Role of Osteopontin as a Diagnostic and Prognostic Biomarker in Sepsis and Septic Shock.

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host-response to infections. Osteopontin (OPN) is an extracellular matrix protein involved in the inflammatory response. Our aim was to evaluate the diagnostic and prognostic performance in sepsis of a single OPN determination in the Emergency Department (ED). We conducted a single-centre prospective observational study in an Italian ED where we enrolled 102 consecutive patients presenting with suspected infection and qSOFA ≥ 2. OPN plasma concentration was found to be an independent predictor of sepsis (OR = 1.020, 95% CI 1.002⁻1.039, P = 0.031) and the diagnostic receiver operating characteristic (ROC) curve resulted in an area under the curve (AUC) of 0.878. OPN levels were positively correlated to plasma creatinine (r = 0.401 with p = 0.0001), but this relation was not explained by the development of acute kidney injury (AKI), since no difference was found in OPN concentration between AKI and non-AKI patients. The analysis of 30-days mortality showed no significant difference in OPN levels between alive and dead patients (p = 0.482). In conclusion, a single determination of OPN concentration helped to identify patients with sepsis in the ED, but it was not able to predict poor prognosis in our cohort of patients.

The increase in copeptin levels in mild head trauma does not predict the severity and the outcome of brain damage.

AIM: To investigate the copeptin prognostic role in mild head trauma. METHODS: We enrolled 105 adult patients who entered the emergency room because of recent mild head trauma; we evaluated: clinical picture, imaging and laboratory data (including copeptin). RESULTS: Copeptin resulted higher in mild head trauma patients compared with controls: 29.89 pmol/l versus 7.05 pmol/l (p = 0.0008). Copeptin failed in identifying patients with or without brain lesions detected by CT scan, and patients with or without adverse events during the 30 days follow-up. CONCLUSION: We confirmed that mild head trauma patients have a significantly higher copeptin plasma levels compared with controls. Nevertheless, we did not observe a significant role for copeptin in traumatic brain injury patients regarding brain damage and outcome.

Gas6 as a predictor of esophageal varices in patients affected by hepatitis C virus related-chronic liver disease.

AIM: Plasma Gas6 was tested as an alternative to Baveno VI criteria (liver stiffness <20 kPa and platelet count >150 × 109/l) in an endoscopy-sparing strategy. METHODS:  A total of 160 patients with chronic hepatitis C and advanced fibrosis/cirrhosis underwent, on the same occasion, liver elastography, upper endoscopy, a platelet count and serum Gas6 measurement. RESULTS:  A total of 74/160 (46%) patients had esophageal varices, that were small (diameter <5 mm) in 57/160 (34%) and large in 17/160 (11%) cases. A total of 34/160 (21%) patients satisfied Baveno VI criteria, according to which screening for esophageal varices could have been omitted; 1/34 had large varices (sensitivity 94%). A plasma Gas6 value <45 ng/ml, detected in 34/160 (21%) patients, was also 94% sensitive. CONCLUSION: Plasma Gas6 might represent a feasible alternative to Baveno VI criteria when transient elastography is unavailable/unsuccessful.