Development of ARPE-19-Equipped Ocular Cell Model for In Vitro Investigation on Ophthalmic Formulations

Repeated intravitreal (IVT) injections in the treatment of retinal diseases can lead to severe complications. Developing innovative drug delivery systems for IVT administration is crucial to prevent adverse reactions, but requires extensive investigation including the use of different preclinical models (in vitro, ex vivo and in vivo). Our previous work described an in vitro tricompartmental ocular flow cell (TOFC) simulating the anterior and posterior cavities of the human eye. Based on promising preliminary results, in this study, a collagen scaffold enriched with human retinal pigmented epithelial cells (ARPE-19) was developed and introduced into the TOFC to partially mimic the human retina. Cells were cultured under dynamic flow conditions to emulate the posterior segment of the human eye. Bevacizumab was then injected into the central compartment of the TOFC to treat ARPE-19 cells and assess its effects. The results showed an absence of cytotoxic activity and a significant reduction in VEGF fluorescent signal, underscoring the potential of this in vitro model as a platform for researching new ophthalmic formulations addressing the posterior eye segment, eventually decreasing the need for animal testing.

Extracellular Vesicles: New Players in the Mechanisms of Sepsis- and COVID-19-Related Thromboinflammation

Sepsis and COVID-19 patients often manifest an imbalance in inflammation and coagulation, a complex pathological mechanism also named thromboinflammation, which strongly affects patient prognosis. Extracellular vesicles (EVs) are nanoparticles released by cells into extracellular space that have a relevant role in cell-to-cell communication. Recently, EVs have been shown to act as important players in a variety of pathologies, including cancer and cardiovascular disease. The biological properties of EVs in the mechanisms of thromboinflammation during sepsis and COVID-19 are still only partially known. Herein, we summarize the current experimental evidence on the role of EVs in thromboinflammation, both in bacterial sepsis and in COVID-19. A better understanding of EV involvement in these processes could be useful in describing novel diagnostic and therapeutic applications of EVs in these diseases.

Thrombopoietin participates in platelet activation in COVID-19 patients

BACKGROUND

The pathogenesis of coronavirus disease 2019 (COVID-19) is characterized by enhanced platelet activation and diffuse hemostatic alterations, which may contribute to immunothrombosis/thromboinflammation and subsequent development of target-organ damage. Thrombopoietin (THPO), a growth factor essential to megakariocyte proliferation, is known to prime platelet activation and leukocyte-platelet interaction. In addition, THPO concentrations increase in several critical diseases, such as acute cardiac ischemia and sepsis, thus representing a potential diagnostic and prognostic biomarker. Furthermore, several data suggest that interleukin (IL)-6 is one of the most important inflammatory mediators involved in these phenomena, which led to explore the potential therapeutic role of IL-6 inhibitors. In this prospective cohort study, we aimed to study THPO and IL-6 concentrations in COVID-19 patients at the time of first clinical evaluation in the Emergency Department (ED), and to investigate their potential use as diagnostic and prognostic biomarkers. In addition, we sought to explore the role of THPO contained in plasma samples obtained from COVID-19 patients in priming in vitro platelet activation and leukocyte-platelet interaction.

METHODS

We enrolled 66 patients presenting to the ED with symptoms suggestive of COVID-19, including 47 with confirmed COVID-19 and 19 in whom COVID-19 was excluded (Non-COVID-19 patients). As controls, we also recruited 18 healthy subjects. In vitro, we reproduced the effects of increased circulating THPO on platelet function by adding plasma from COVID-19 patients or controls to platelet-rich plasma or whole blood obtained by healthy donors, and we indirectly studied the effect of THPO on platelet activation by blocking its biological activity.

FINDINGS

THPO levels were higher in COVID-19 patients than in both Non-COVID-19 patients and healthy subjects. Studying THPO as diagnostic marker for the diagnosis of COVID-19 by receiver-operating-characteristic (ROC) statistics, we found an area under the curve (AUC) of 0.73, with an optimal cut-off value of 42.60 pg/mL. IL-6 was higher in COVID-19 patients than in healthy subjects, but did not differ between COVID-19 and Non-COVID-19 patients. THPO concentrations measured at the time of diagnosis in the ED were also higher in COVID-19 patients subsequently developing a severe disease than in those with mild disease. Evaluating THPO as biomarker for severe COVID-19 using ROC analysis, we found an AUC of 0.71, with an optimal cut-off value of 57.11 pg/mL. IL-6 was also higher in severe than in mild COVID-19 patients, with an AUC for severe COVID-19 of 0.83 and an optimal cut-off value of 23 pg/ml. THPO concentrations correlated with those of IL-6 (r=0.2963; p=0.043), and decreased 24 h after the administration of tocilizumab, an IL-6 receptor blocking antibody, showing that the increase of THPO levels depends on IL-6-stimulated hepatic synthesis. In vitro, plasma obtained from COVID-19 patients, but not from healthy subjects, primed platelet aggregation and leukocyte-platelet binding, and these effects were reduced by inhibiting THPO activity.

INTERPRETATION

Increased THPO may be proposed as an early biomarker for the diagnosis of COVID-19 and for the identification of patients at risk of developing critical illness. Elevated THPO may contribute to enhance platelet activation and leukocyte-platelet interaction in COVID-19 patients, thus potentially participating in immunothrombosis/thromboinflammation.

FUNDING

This work was supported by Ministero dell'Università e della Ricerca Scientifica e Tecnologica (MURST) ex 60% to GM and EL.

Thrombopoietin Contributes to Enhanced Platelet Activation in Patients with Type 1 Diabetes Mellitus

Atherosclerotic cardiovascular disease is the major cause of morbidity and mortality in patients with type 1 diabetes mellitus (T1DM). Enhanced platelet reactivity is considered a main determinant of the increased atherothrombotic risk of diabetic patients. Thrombopoietin (THPO), a humoral growth factor able to stimulate megakaryocyte proliferation and differentiation, also modulates the response of mature platelets by enhancing both activation and binding to leukocytes in response to different agonists. Increased THPO levels have been reported in different clinical conditions characterized by a generalized pro-thrombotic state, from acute coronary syndromes to sepsis/septic shock, and associated with elevated indices of platelet activation. To investigate the potential contribution of elevated THPO levels in platelet activation in T1DM patients, we studied 28 T1DM patients and 28 healthy subjects. We measured plasma levels of THPO, as well as platelet-leukocyte binding, P-selectin, and THPO receptor (THPOR) platelet expression. The priming activity of plasma from diabetic patients or healthy subjects on platelet–leukocyte binding and the role of THPO on this effect was also studied in vitro. T1DM patients had higher circulating THPO levels and increased platelet–monocyte and platelet–granulocyte binding, as well as platelet P-selectin expression, compared to healthy subjects, whereas platelet expression of THPOR did not differ between the two groups. THPO concentrations correlated with platelet–leukocyte binding, as well as with fasting glucose and Hb1Ac. In vitro, plasma from diabetic patients, but not from healthy subjects, primed platelet–leukocyte binding and platelet P-selectin expression. Blocking THPO biological activity using a specific inhibitor prevented the priming effect induced by plasma from diabetic patients. In conclusion, augmented THPO may enhance platelet activation in patients with T1DM, potentially participating in increasing atherosclerotic risk.

Impact of Tissue Enolase 1 Protein Overexpression in Esophageal Cancer Progression

Enolase (ENO) 1 is a key glycolytic enzyme and important player in tumorigenesis. ENO1 overexpression has been correlated with tumor progression and/or worse prognosis in several solid malignancies. However, data concerning the impact of ENO1 in cancer conflict. The study correlated local and circulating ENO1 protein levels in esophageal cancer (EC) with clinicopathological data, to assess its potential clinical value. ENO1 expression was analyzed by immunohistochemistry in paired tumor and non-tumor tissue samples from 40 EC cases and mucosal biopsies from 45 Barrett's esophagus (BE) cases, plus in plasma from these patients and 25 matched healthy controls. ENO1 was abnormally elevated in cancer-cell cytoplasm in both EC types, in esophageal squamous cell carcinoma and in adenocarcinoma (EAC), increasing significantly with tumor stage progression and the transition from BE to EAC. EAC patients exhibited significantly lower ENO1 plasma concentrations than normal subjects. Neither local nor systemic ENO1 expression levels were significantly associated with overall survival. These results indicate ENO1 as potential biomarker, delineating a population of patients with Barrett's esophagus at high risk of cancer, and as new therapeutic opportunity in EC patient management. However, further confirmation might be necessary.

Thymic stromal lymphopoietin in human pancreatic ductal adenocarcinoma: expression and prognostic significance

Thymic stromal lymphopoietin (TSLP) has emerged as an important, but contradictory, player conditioning tumor growth. In certain contexts, by driving T helper (h) 2 responses via tumor-associated OX40 Ligand (OX40L)⁺ dendritic cells (DCs), TSLP may play a pro-tumorigenic role. The study elucidates the importance of TSPL in pancreatic ductal adenocarcinoma (PDAC), by analyzing: i) TSLP levels in PDAC cell-line supernatants and plasma from patients with locally-advanced/metastatic PDAC, pre- and post-treatment with different chemotherapeutic protocols, in comparison with healthy donors; ii) TSLP and OX40L expression in PDAC and normal pancreatic tissues, by immunohistochemistry; iii) OX40L expression on ex vivo-generated normal DCs in the presence of tumor-derived TSLP, by flow cytometry; iv) clinical relevance in terms of diagnostic and prognostic value and influence on treatment modality and response.

Some PDAC cell lines, such as BxPC-3, expressed both TSLP mRNA and protein. Normal DCs, generated ex vivo in the presence of TSLP-rich-cell supernatants, displayed increased expression of OX40L, reduced by the addition of a neutralizing anti-TSLP polyclonal antibody. OX40L⁺ cells were detected in pancreatic tumor inflammatory infiltrates. Abnormally elevated TSLP levels were detected in situ in tumor cells and, systemically, in locally-advanced/metastatic PDAC patients. Of the chemotherapeutic protocols applied, gemcitabine plus oxaliplatin (GEMOX) significantly increased circulating TSLP levels. Elevated plasma TSLP concentration was associated with shorter overall survival and increased risk of poor outcome. Plasma TSLP measurement successfully discriminated PDAC patients from healthy controls.

These data show that TSLP secreted by pancreatic cancer cells may directly impact PDAC biology and patient outcome.

Platelets and Multi-Organ Failure in Sepsis

Platelets have received increasing attention for their role in the pathophysiology of infectious disease, inflammation, and immunity. In sepsis, a low platelet count is a well-known biomarker for disease severity and more recently authors have focused their attention on the active role of platelets in the pathogenesis of multi-organ failure. Septic shock is characterised by a dysregulated inflammatory response, which can impair the microcirculation and lead to organ injury. Being at the crossroads between the immune system, clotting cascade, and endothelial cells, platelets seem to be an appealing central mediator and possible therapeutic target in sepsis. This review focuses on the pathogenic role of platelets in septic organ dysfunction in humans and animal models.

A Xenogenic Bone Derivative as a Potential Adjuvant for Bone Regeneration and Implant Osseointegration: An In Vitro Study

Several clinical conditions may limit the success of bone regeneration and/or implant osseointegration. For this reason, many compounds have been tested for their ability to stimulate this biological process. Synthetic hydroxyapatite (HA), mimicking natural bone hydroxyapatite, and extra-cellular matrix proteins, such as type I collagen, are potential candidates. However, the synthetic origin of HA and the denaturing conditions required for extracting collagen from skin and derma are sources of potential drawbacks. This study examines the in vitro effects of a natural bone derivative (NBD) extracted from equine bone and containing both natural, non-synthetic bone hydroxyapatite and native, non-denatured, type I bone collagen as a possible active compound for stimulating bone regeneration and implant osseointegration. The activity of NBD was tested on bone marrow stromal cells (BMSCs), evaluating their growth/viability by the methylthiazol tetrazolium (MTT) assay and their migration potential by a scratch assay. Moreover, expression of the hyaluronic acid receptor (CD44) and the C-X-C chemokine receptor type 4 (CXCR4, CD184) on the surface of BMSCs was assessed by flow cytometry, and the release of Transforming Growth Factor (TGF)-β, Interleukin (IL)-1α and IL-6 was quantified using an enzyme-linked immunosorbent assay (ELISA). The effect of NBD-coated implants on human osteoblasts was tested by measuring alkaline phosphatase (ALP) activity with the p-nitrophenyl phosphate (pNPP) degradation test. NBD stimulated BMSC growth/viability, migration, CD184 surface expression and the release of TGF-β1. NBD-coated implants increased ALP activity of human osteoblasts. These results indicate that NBD may be an adjuvant to accelerate both bone regeneration and osseointegration.

May thrombopoietin be a useful marker of sepsis severity assessment in patients with SIRS entering the emergency department?

BACKGROUND

Thrombopoietin (TPO), a growth factor primarily involved in regulating thrombopoiesis, has been recently implicated in the pathogenesis of sepsis. TPO levels are, indeed, greatly increased in patients with sepsis compared to control subjects, and correlate with sepsis severity. The aim of this study was to evaluate TPO as predictive biomarker of sepsis and of sepsis severity in patients entering the emergency department (ED) with systemic inflammatory response syndrome (SIRS).

METHODS

This was a prospective observational study. Ours is a sub-study of the 'Need-speed trial', a multi-center observational study involving six Italian centers affiliated to the GREAT Italian Network. TPO was measured by ELISA.

RESULTS

We enrolled 13 patients with SIRS (6 with acute pancreatitis, 3 with acute heart failure, 1 with pulmonary embolism, and 3 with allergic reactions), and 40 patients with sepsis, eight of whom had severe sepsis and three septic shock. TPO was significantly higher in patients with sepsis than with SIRS. In addition, TPO was higher in patients with severe sepsis than with sepsis, and in patients with septic shock than with severe sepsis, although these differences did not reach the statistical significance.

CONCLUSIONS

Our preliminary results suggest that TPO may have the potential to be considered a promising early biomarker for both the diagnosis of sepsis and the assessment of sepsis severity in patients with SIRS entering the ED.

Eosinophilic inflammation of chronic rhinosinusitis with nasal polyps is related to OX40 ligand expression

The aims of this study were to investigate OX40 ligand expression in sinus tissue from patients with nasal polyposis compared with patients with chronic rhinosinusitis without nasal polyps (NPs), and to determine if OX40 ligand expression is related to eosinophilic sinus infiltration. Twenty patients with chronic rhinosinusitis (11 with and nine without NPs) and seven controls were enrolled in the study. The mRNA expression of OX40 ligand and thymic stromal lymphopoietin and its receptor were analyzed. The immunoreactivity score for OX40 ligand and the eosinophil count were obtained. The mRNA expression and immunoreactivity score of OX40 ligand were higher in patients with nasal polyposis than in patients without NPs, as well as healthy controls. The mRNA expression of thymic stromal lymphopoietin and its receptor was significantly higher in nasal polyposis than in the control, but not significantly higher than in chronic rhinosinusitis without NPs. A correlation between the number of OX40 ligand-positive cells and the number of eosinophils in sinus biopsies was found only in patients with nasal polyposis. In conclusion, the thymic stromal lymphopoietin/OX40 ligand axis is up-regulated in nasal polyposis and is related to the intensity of eosinophilic inflammation.

Pancreatic-carcinoma-cell-derived pro-angiogenic factors can induce endothelial-cell differentiation of a subset of circulating CD34+ progenitors

Background

CD34⁺ progenitor cells comprise both hematopoietic and endothelial progenitor cells. Recent studies suggest that circulating endothelial progenitor cells are recruited into the angiogenic vascular system of several cancers, including pancreatic carcinoma, and that they correlate with clinical progress. However, whether endothelial progenitor cell mobilization occurs in response to cytokine release by tumor cells is still unclear.

Methods

The chemotactic- and/or differentiating-activities of the poorly-differentiated pancreatic carcinoma cell line PT45, and of the immortal H6c7 cell line, a line of near-normal pancreatic duct epithelial cells, on endothelial progenitor cells were investigated in vitro using circulating CD34⁺ as model.

Results

The study showed that Vascular Endothelial Growth Factor produced by PT45 cells and, at lesser extent, by H6c7 cells, predominantly chemoattract peripheral blood CD34⁺ expressing the type 2 relative receptor. Addition of PT45-conditioned medium to CD34⁺ cells, cultured under conditions supporting myeloid cell development, diverted the differentiation of a subset of these progenitor cells into cells expressing endothelial cell markers, such as CD146, CD105, VE-cadherin and von Willebrand Factor-related antigen. Moreover, these endothelial-like cells formed capillary networks in vitro, chiefly through the release of Angiopoietin-1 by PT45 cells.

Conclusions

The results demonstrate that pancreatic-carcinoma cells potentially attract circulating endothelial progenitor cells to the tumor site, by releasing high levels of pro-angiogenic factors such as Vascular Endothelial Growth Factor and Angiopoietin-1, and may direct the differentiation of these cell subsets of the CD34⁺ cell population into endothelial cells; the latter cells may become a component of the newly-formed vessels, contributing to angiogenesis-mediated tumor growth and metastasis.

Potential plasticity of T regulatory cells in pancreatic carcinoma in relation to disease progression and outcome

CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) are understood to maintain peripheral tolerance to self-antigens and inhibit antitumor immune responses. However, compelling evidence suggests that, Tregs provide no anti-inflammatory protection in the tumor microenvironment, but rather contribute to a T helper 17 (Th17)-driven pro-carcinogenic process. Using three-color flow cytometry, we evaluated the percentage of circulating CD4(+)CD25(+)FoxP3(+) Tregs in the peripheral blood of pancreatic carcinoma patients prior to and after chemotherapy [gemcitabine (GEM) alone, or GEM+oxaliplatin (GEMOX) or bevacizumab+capecitabine+radiotherapy (BEV+CAPE+RT)]. Correlations were sought between Treg counts and plasma levels of cytokines relevant to controlling the Treg/Th17 balance, i.e., interleukin (IL)-23, IL-17A, IL-6 and transforming growth factor β 1 (TGF-β1), as measured by ELISA and the clinical features of pancreatic cancer. Treg, IL-6 and TGF-β1 levels were higher in locally advanced and metastatic pancreatic carcinoma patients compared to controls. No parameter was correlated with disease stage except IL-6. IL-17A and TGF-β1 were significantly associated with increased risk of poor prognosis. IL-17A was positively correlated with IL-23. Treg and IL-6 levels decreased following GEM monochemotherapy, IL-17A levels decreased after GEMOX, and IL-6 levels were reduced subsequent to BEV+CAPE+RT treatment. IL-23, IL-17A and TGF-β1 levels were significantly lower in patients responding to chemotherapy (partial remission/stable disease) than in nonresponders to chemotherapy (progressive disease). These results suggest an impact of the Treg/Th17-balance in pancreatic carcinoma, highlighting the significance of TGF-β1 and IL-17A as potential prognostic and predictive indicators. Immunological changes induced by mono and/or combined chemotherapy indicate specific windows of opportunity for introducing integrative interventions on a new target in pancreatic cancer, i.e. IL-17A, possibly improving survival in this highly lethal disease.

The expression of TSLP receptor in chronic rhinosinusitis with and without nasal polyps

Chronic Rhinosinusitis with or without Nasal Polyps (CRSwNP and CRSsNP) may be characterized by different cytokine profiles. Generally, Th2 cytokines and eosinophilic infiltration have been reported to be more specific of CRSwNP compared to CRSsNP, where neutrophils seem to play a major role. The epithelial cell-derived thymic stromal lymphopoietin (TSLP) has been recently identified as a key factor in Th2-inflammatory response. The aim of this study is to investigate the expression of TSLP Receptor (TSLP R) in surgical specimens obtained from patients affected by CRSwNP (n=10) and CRSsNP (n=5) by immunohistochemical techniques (immunostaining score, IS). TSLP R expression was significantly higher in the inflammatory infiltrate and in the epithelial cells of CRSwNP, CRSsNP patients compared to the control group (IS 4.5±0.68, 4.4±1.44 and 0.43±0.3 respectively, p=0.0024 for inflammatory infiltrate and IS 5.8±0.92, 7.8±2.06 and 0.86±0.55 respectively, p=0.0018 for epithelial cells). No significant difference was observed in IS of inflammatory infiltrate and epithelial cells in CRSwNP compared to CRSsNP. Very low IS for TSLP R was found in connective tissue of all the samples, with no difference among the groups. TSLP receptor is highly expressed in CRS compared to controls and independently from the polyps suggesting an early common inflammatory pathway in the two CRS phenotypes.

Comparative evaluation of cancer stem cell markers in normal pancreas and pancreatic ductal adenocarcinoma

Chemoresistance and self-renewal of cancer stem cells (CSC), found in many tumors including pancreatic ductal adenocarcinoma (PDAC), are believed to underlie tumor mass regrowth. The distribution of cells carrying the putative stem-cell markers CD133, Nestin, Notch1-4, Jagged1 and 2, ABCG2 and aldehyde dehydrogenase (ALDH1) was assessed immunohistochemically using PDAC and normal pancreas tissue microarrays. The immunoreactivity was semi-quantitatively graded against the normal pancreas and was correlated with the differentiation grade and disease stage. No statistical significant differences were found between normal pancreas and PDAC in the expression of Nestin, Notch1, 3 and 4, ABCG2 or ALDH1. Notch2 and Jagged1 and 2 expression were increased in PDAC. CD133-positive cells were above-normal in PDAC, but the difference was not statistically significant. Nestin, Notch1-4, Jagged1, ABCG2 and ALDH1 immunostaining scores were not correlated with tumor grade or disease stage. CD133 and Notch2 expression was significantly inversely correlated with tumor grade, but not disease stage. Notch3 immunostaining positively correlated with tumor stage, but not with differentiation grade. Jagged2 protein expression correlated inversely with disease stage, but not with tumor grade. From the clinical standpoint, improved delineation of the tumor CSC signature, putatively responsible for tumor initiation and recurrence after initial response to chemotherapy, may offer novel therapeutic targets for this highly lethal cancer.

Abnormal expression of Endoglin and its receptor complex (TGF-β1 and TGF-β receptor II) as early angiogenic switch indicator in premalignant lesions of the colon mucosa

The precise timing of the angiogenic switch in colorectal cancer development is still unclear. The simultaneous expression of Endoglin (CD105), transforming growth factor (TGF)-β1 and TGF-β receptor (R) II were quantified in surgical specimens comprising normal human colon, pre-malignant dysplastic tissue, in situ, and invasive colon cancer specimens, at mRNA and protein levels, respectively by real-time PCR and immunohistochemistry. Serum concentrations of soluble Endoglin and TGF-β1 were evaluated. mRNA and CD105+-microvessel density (MVD) increased significantly in dysplastic colon and carcinoma versus normal tissues; values correlated respectively with dysplasia degree and Dukes' stages. TGF-β1 expression was significantly upregulated in most severe dysplastic adenoma specimens, while TGF-β1 transcript and protein signals were intense in carcinoma, positively-correlated with tumor progression. TGF-β1 RII was overexpressed in adenoma and carcinoma versus normal samples, but unrelated with dysplasia or Dukes' stage. Soluble Endoglin serum levels were equivalent in adenoma and normal tissues; in carcinoma the highest levels were in invasive tumor. Circulating TGF-β1 levels were increased in severe dysplasia and progressed with tumor progression. Correlations between adenoma dysplasia degree and TGF-β RII and CD105+-MVD, and between tumor Dukes' staging and TGF-β1 and CD105+-MVD, were significant. TGF-β1 and Endoglin and TGF-β1 serum levels, TGF-β1 staining and CD105+-MVD were significantly and inversely associated with disease-free survival. TGF-β1 levels were an independent and significant prognostic factor of disease-free survival. These findings suggest active angiogenesis occurs in many pre-malignant colon cases and supports more careful evaluation of different chemopreventive agents.

Pilot study to relate clinical outcome in pancreatic carcinoma and angiogenic plasma factors/circulating mature/progenitor endothelial cells: Preliminary results

Circulating endothelial cells (CEC) and bone marrow-derived endothelial progenitors (ECP) play important roles in tumor growth and have been proposed as non-invasive markers of angiogenesis. However, CEC and ECP levels have not been investigated in pancreatic carcinoma patients. Using four-color flow cytometry procedures, we evaluated the count of resting (rCEC) and activated (aCEC) endothelial cells and ECP in the peripheral blood of pancreatic carcinoma patients before and after chemotherapy, consisting of gemcitabine (GEM) alone or in combination with oxaliplatin (OX), or with 5-fluorouracil (5-FU). We also correlated CEC and ECP levels with plasma levels of relevant angiogenic factors, such as vascular endothelial growth factor (VEGF)-A, VEGF-D, angiopoietin (Angio)-1, and chemokine C-X-C motif ligand (CXCL)12, measured by ELISA, and with clinical features of pancreatic cancer. The aCEC, rCEC, ECP, and VEGF-A plasma levels were significantly higher in locally-advanced and metastatic patients than controls. Both ECP and VEGF-A levels correlated positively with disease stage and inversely with patient's overall survival. Measurements after the treatment course showed that VEGF-A plasma concentrations and ECP counts had decreased significantly. In particular, VEGF-A and rCEC were significantly down after treatment with GEM alone or in combination with OX. No significant differences in terms of circulating angiogenic factor or endothelial cell subtype levels were found between responders (patients entering partial remission or with stable disease) and non-responders (patients with progressive disease). The study provides insights into angiogenesis mechanisms in pancreatic carcinoma, for which anti-angiogenic targeting of VEGF-A and ECP could be of interest.

Pro-oxidant and proapoptotic effects of cholesterol oxidation products on human colonic epithelial cells: a potential mechanism of inflammatory bowel disease progression

With the aim of investigating whether cholesterol oxidation products could contribute to the pathogenesis of the intestinal epithelial barrier dysfunction that occurs in human inflammatory bowel disease (IBD), differentiated versus undifferentiated CaCo-2 cells, an accepted model for human intestinal epithelial cells, were challenged with a dietary-representative mixture of oxysterols. Only differentiated colonic cells were susceptible to the proapoptotic action of the oxysterol mixture, checked both by enzymatic and by morphological methods, mainly because of a very low AKT phosphorylation pathway compared to the undifferentiated counterparts. Enhanced production of reactive oxygen species by a colonic NADPH oxidase hyperactivation seemed to represent the key event in oxysterol-induced up-regulation of the mitochondrial pathway of programmed death of differentiated CaCo-2 cells. These in vitro findings point to the pro-oxidant and cytotoxic potential of cholesterol oxidation products, of both dietary and endogenous origin, as an important mechanism of induction and/or worsening of the functional impairment of enteric mucosa that characterizes IBD.

Impact of surgery and chemotherapy on cellular immunity in pancreatic carcinoma patients in view of an integration of standard cancer treatment with immunotherapy

As surgery and chemotherapy may act as adjuvants providing antitumor immunity benefits, we ran phenotypical and functional immunomonitoring in patients with resectable pancreatic adenocarcinoma and advanced metastatic disease receiving combined treatment (cisplatin, gemcitabine, 5-FU). Blood was taken before/one month after resection; before/during chemotherapy. Controls were age- and gender-matched. Circulating lymphocyte, myeloid and plasmacytoid dendritic cell (MDC and PDC) subsets were examined by flow cytometry; functional activity by mixed lymphocyte reaction (MLR) for DC allostimulation, through 4-h 51Cr-release assay for Natural Killer (NK) and lymphokine-activated-killer (LAK) cell cytotoxicity; ELISA for spontaneous/activated cytokine release by PBMC and T cells. Significant differences occurred in several parameters between pretreatment patient and control values: fewer CD8+ cells and increased apoptosis-prone CD3+/CD95+ lymphocytes, higher frequency of MDC, reduced allostimulatory activity by ex vivo-generated DC, depressed LAK activity, elevated IL-10 and IL-12p40 production; impaired IL-12p70 and IFN-gamma production by stimulated PBMC and T cells. Only IL-12p70 level was correlated with survival. One month after radical, but not palliative surgery, the percentage of T-lymphocytes coexpressing CD3/CD95 decreased significantly, the stimulatory capacity of DC increased, and LPS-induced IL-12p70 release by PBMC rose concomitantly with the anti-CD3 stimulated-IFN-gamma production by T cells. In patients with locally advanced or metastatic disease, one and/or two combined drug cycles increased percentage of CD4+ cells and LAK cell cytotoxicity and decreased PDC frequency and spontaneous/LPS-stimulated IL-10 by PBMC. Results suggest immunological changes induced by surgical resection/combined chemotherapy indicate specific precisely-timed windows of opportunity for introducing immunotherapy in pancreatic cancer, possibly improving survival in this highly lethal disease.

4-Hydroxynonenal is Markedly Higher in Patients on a Standard Long-term Home Parenteral Nutrition

Parenteral nutrition, a commonly used procedure in patients with gastrointestinal disorders, may lead with time to liver steatosis and fibrosis, whose pathogenesis has yet to be elucidated. Oxidative stress and particularly lipid peroxidation likely contribute to the expression of such hepatobiliary complications, by means of their recognized proinflammatory and profibrogenic effects. To evaluate the adequacy against oxidative insult of a standard micronutrient supplementation in patients under long term parenteral nutrition, a comprehensive patterns of redox indices has been determined on peripheral blood samples from forty one adults in comparison to fifty eight blood donors taken as controls. A sustained oxidative stress in peripheral blood of home parenteral patients was observed. Of the two lipid peroxidation markers found to be markedly increased, namely fluorescent plasma protein adducts with malondialdehyde and 4-hydroxynonenal, respectively, only the second was statistically correlated with all the antioxidant-related changes consistently detected in the patients, namely decreased plasma alpha-tocopherol and selenium intake and higher erythrocyte oxidized glutathione. Plasma level of 4-hydroxynonenal-protein adducts appears to be a reliable and easily measurable marker of oxidative status, particularly indicated to monitor the adequacy of dietary regimen during parenteral nutrition.

AT1 receptor antagonist Candesartan in selected cirrhotic patients: effect on portal pressure and liver fibrosis markers

BACKGROUND/AIMS

The renin-angiotensin system plays an important role in hepatic fibrogenesis and in portal hypertension. To examine the long-term effects of Candesartan cilexetil, an angiotensin type 1 (AT1) receptor blocker, on portal-systemic haemodynamics and on liver fibrosis.

METHODS

Forty-seven compensated Child A and Child B (8) cirrhotic patients were randomly assigned to receive Candesartan cilexetil, 8 mg/d (N.24) and no treatment (N.23) for 1 year. Portal-systemic haemodynamic parameters, serological levels of procollagen (PIIINP), hyaluronic acid (HA) and transforming growth factor beta 1 (TGFbeta1) were assessed at baseline and after 12 months.

RESULTS

No patients discontinued or decreased the drug. The hepatic venous pressure gradient (HVPG) decreased significantly in treated patients (-8.4%+/-2.4) with a reduction >20% in 25% of cases vs+5.6%+/-2.9 in the untreated group. HA plasma levels decreased significantly in Candesartan treated patients in whom HVPG diminished and rose in untreated patients in whom HVPG increased.

CONCLUSIONS

In selected cirrhotic patients, pharmacological inhibition of the AT1 receptor is well tolerated and induced a mild reduction of portal pressure. This haemodynamic effect might be related to liver fibrogenesis activity.

c-Jun N-terminal kinase upregulation as a key event in the proapoptotic interaction between transforming growth factor-beta1 and 4-hydroxynonenal in colon mucosa

Cells of colonic mucosa are sensitive to the Smad-mediated growth-inhibitory effect of transforming growth factor-beta1 (TGF-beta1). Another important cell growth inhibitor is the polyunsaturated lipid peroxidation end product, 4-hydroxynonenal (HNE), which triggers apoptosis through c-Jun N-terminal kinase (JNK) activation. Interestingly, a close association between TGF-beta1 and HNE was found in the progression of human colon cancer, with concentration of both molecules inversely related to the malignancy. We investigated the cross talk between Smads and JNK signal transduction pathways in inducing apoptosis. To this purpose TGF-beta1 and HNE were added singly or in combination to CaCo-2 human colon adenocarcinoma cells. The cotreatment induced a marked enhancement of apoptosis and of JNK and Smad4 activities much more than either individual molecule. Cell preincubation with the JNK inhibitor SP600125 significantly prevented JNK and Smad4 enhancement and, subsequently, the cooperative proapoptotic effect was abolished. The primary role of JNK activity in TGF-beta1/HNE cooperative signaling was fully confirmed in a second set of experiments by using JNKi I, a more selective kinase inhibitor. Hence, in tumor cells becoming resistant to TGF-beta1-mediated growth inhibition, increased induction of the remaining TGF-beta1 pathways by interaction with other antiproliferative molecules, such as HNE, could help in inhibiting tumor growth.

Early involvement of ROS overproduction in apoptosis induced by 7-ketocholesterol

Cholesterol oxidation products are increasingly considered as much more bioactive than the parent compound in the multifactor and multistep process that characterizes atherosclerosis. In particular, 7-ketocholesterol has been reported to induce oxidative stress as well as a marked pro-apoptotic effect in vascular cells including macrophages. With the aim to investigate a possible pathogenic correlation between the two events, cultivated murine macrophages were challenged with a concentration of 7-ketocholesterol actually detectable in human vasculature. Conclusive proof was obtained of a primary role of NADPH-oxidase in the overproduction of reactive oxygen species within cells treated with the oxysterol. In addition, such oxidative burst occurred very early after cell intoxication and it was definitely demonstrated as able to lead cells to apoptotic death. In fact, two metabolic inhibitors of NADPH-oxidase and the antioxidant epicatechin very well counteracted 7-ketocholesterol-induced apoptosis by preventing the oxysterol pro-oxidant action.

4-hydroxynonenal and TGF-beta1 concur in inducing antiproliferative effects on the CaCo-2 human colon adenocarcinoma cell line

4-Hydroxynonenal (HNE) has been demonstrated to exert its antiproliferative effect by up-regulating the c-Jun-N-terminal kinase (JNK), a member of the mitogen-activated protein kinase family (MAPKs). Transforming growth factor-beta1 (TGF-beta1) is the major negative regulatory factor in controlling cell proliferation, and Smads are its intracellular transducers. Recent data on human colon adenocarcinoma has shown a low HNE content paralleled by a marked alteration of TGF-beta1 levels within the tumor mass. The two events appear related because of the demonstrated marked ability of HNE to up-regulate expression and synthesis of TGF-beta1; the combined decreases of HNE and TGF-beta1 found in cancer cells provide a favorable condition for neoplastic progression. Furthermore, HNE is likely able to interact with the cytokine to enhance apoptosis and increase intracellular reactive oxygen species (ROS) formation in the CaCo-2 colon carcinoma cell line. The probable mechanism whereby HNE and TGF-beta1 interact to induce apoptosis is through cross-talk between the main signaling pathways of the two molecules (JNK and Smads), and the observed ROS production might only contribute to amplifying the apoptotic pathways. The network between the two signaling pathways here involved is now under investigation.

Adipocyte expression and circulating levels of leptin increase in both gynaecological and breast cancer patients

Leptin is a hormone involved in the regulation of body weight and sexual maturation. We previously reported that cancer cachexia was associated with reduced or normal levels of leptin. Here we investigate whether leptin levels are related to cachetic or hormonal status. Circulating leptin and its mRNA from adipose tissue were measured in 87 patients with gynaecological and breast cancers and related to tumour, cachexia and hormonal markers. We found that leptin protein increased in patients with these tumours due to higher mRNA levels. In patients with ovarian cancer, the increased leptin levels were associated with higher circulating follicle-stimulating hormone (FSH). The higher leptin concentrations in patients with endometrial and portio tumours were related to an increase in tissue estrogen receptor (ER) and progesterone receptor (PGR) and, only in the postmenopause, to an increase in circulating estradiol. Patients with breast cancer showed enhanced blood plasma concentrations of progesterone and estradiol, and enhanced tissue levels of ER and PGR associated with increased leptin levels. The data from the present study indicate that, in gynaecological and breast cancers, leptin is related to hormonal status but not to cachexia. We suggest that leptin stimulates the production of sexual hormones, important risk factors for these tumours, and we propose leptin as a novel prognostic marker.

Oxysterol mixtures prevent proapoptotic effects of 7-ketocholesterol in macrophages: implications for proatherogenic gene modulation

Oxysterols are common components of oxidized low-density lipoprotein and accumulate in the core of fibrotic plaques as a mixture of cholesterol and cholesteryl ester oxidation products. The proapoptotic effects of a biologically representative mixture of oxysterols was compared with equimolar amounts of 7-ketocholesterol and unoxidized cholesterol. The oxysterol mixture in a concentration range actually detectable in hypercholesterolemic patients did not stimulate programmed cell death in cultivated murine macrophages. Unoxidized cholesterol also produced no effect. By contrast, when given alone, 7-ketocholesterol strongly stimulated the mitochondrial pathway of apoptosis with cytochrome c release, caspase-9 activation, and eventually caspase-3 activation. Subsequent experiments showed that when 7-ketocholesterol was administered to cells together with another oxysterol, namely 7betaOH-cholesterol, the strong proapoptotic effect of 7-ketocholesterol was markedly attenuated. As regards the mechanism underlying this quenching, we found that the combined oxysterol treatment counteracted the ability of 7-ketocholesterol, when administered alone, to strongly up-regulate the steady-state levels of reactive oxygen species (ROS) without interfering with sterol uptake. Furthermore, this increase in intracellular ROS appeared to be responsible for the up-regulation of proapoptotic factor, p21, after treatment with 7-ketocholesterol but not in cells challenged with the oxysterol mixture. Competition among oxysterols, apparently at the level of NADPH oxidase, diminishes the ROS induction and direct toxicity that is evoked by specific oxysterols. As a consequence, a more subtle gene modulation by oxysterols becomes facilitated in vascular cells.

4-hydroxynonenal and transforming growth factor-beta1 expression in colon cancer

In vivo studies on human colon adenocarcinoma showed decreased transforming growth factor-beta1 (TGF-beta1) antiproliferative cytokine content in tumour tissue related to malignancy progression, with a corresponding decrease in lipid peroxidation aldehydic end-product, 4-hydroxynonenal (HNE). The tumour mechanism to escape TGF-beta1-mediated growth inhibition may be due to an altered TGF-beta1 receptor system. Subsequent in vitro analyses showed a differential distribution of TGF-beta1 receptors depending on the human colon cancer cell line considered (CaCo-2 or HT-29): compared to HT-29 cells, CaCo-2 cells showed a decrease of the two main TGF-beta1 receptors, RI and RII. Notwithstanding their partial TGF-beta1 RI and RII deficiency, treatment of CaCo-2 cells with adequate doses of the cytokine (10 ng/ml) was able to induce apoptosis. Of note, co-treatment of these cells with 1 microM HNE increased the apoptotic effect. The constant low concentration of TGF-beta1 in the tumour mass may be related to the low content of antiproliferative HNE observed in colon cancer: the latter phenomenon, which reduces TGF-beta1 production in the tumour area, may represent a favourable condition for neoplastic progression. The enhancement of TGF-beta1-induced apoptosis by HNE in CaCo-2 cells supports this hypothesis. The different transcriptional components regulated by the distinct signaling pathways of these two molecules might be proposed; in particular, crosstalk between the MAPK and the Smad pathway could modulate and co-operate in the transcription of target genes involved in regulation of cell proliferation.

Cell cholesterol esters and high-density lipoprotein plasma levels during liver hyperplasia in choline-fed male and female rats

Sexual dimorphism exists in the response of rats to lead nitrate, liver hyperplasia occuring earlier and being more pronounced in males. Excess dietary choline in females shifted the growth pattern towards that of males. To determine whether phosphatidylcholine-induced growth modulations could be related to a derangement of cholesterol metabolism, liver accumulation of cholesterol esters and plasma lipoprotein patterns were investigated. In males, lead-induced liver hyperplasia was associated with increased total cholesterol hepatic content, accumulated cholesterol esters and reduced concentration of plasma High Density Lipoprotein (HDL) cholesterol. Females were less responsive to the liver mitogenic signal of lead nitrate; there was no elevation of cholesterol content nor any marked accumulation of cholesterol esters. This is consistent with the lack of change in the plasma levels of HDL cholesterol. Continuous choline feeding displaced the liver cholesterol ester pattern and plasma HDL cholesterol levels in females, and in parallel that of DNA synthesis, towards those of males. Choline was not observed to have any effect in males. These results suggest that the derangement of phosphatidylcholine metabolism induces growth-related changes in cholesterol turnover; they are consistent with the proposal that the intracellular content of cholesterol esters may have a role in regulating liver growth rates.

Leptin expression in colorectal and breast cancer patients

Leptin is a hormone which controls fat metabolism. Leptin plasma levels and adipose tissue mRNA expression were measured in cancer patients. Plasma levels were correlated with TNM staging, cachexia parameters, tumour markers and hormones. Breast and colorectal cancer patients showed blood plasma levels of insulin, TNF-alpha and tumour markers higher than controls. Breast cancer patients, but not colorectal cancer patients, had plasma levels and adipose tissue expression of leptin significantly higher than controls associated with elevated values of estrogen- and progesterone-receptors. These data suggest the possible use of leptin as a clinical marker.