Cardioprotection by Targeting the Pool of Resident and Extracardiac Progenitors

The adult heart has the capacity to generate new myocytes that are markedly enhanced in acute and chronic heart failure of ischemic and non-ischemic origin. In addition, a pool of blood trafficking progenitor cells able to sense myocardial damage may home to the sites of injury participating to cardiac repair. This new view of myocardial biology leads to an expanding long-term research and therapeutic goals for cardioprotection. A fundamental concept to be analyzed is whether cardiac diseases are influenced by changes in the properties of tissue specific and circulating progenitors. Loss of self-renewal capacity, impaired growth or increased susceptibility to death may lead to a reduction of progenitors and leave myocardial damage unrepaired. Cardiac progenitors generate all myocardial cell lineages, thus impairment in their growth is expected to be critically involved in the structural and functional modifications of the heart. The fact that, in addition to well known effects of anthracyclines, also new drugs that target molecular pathways implicated in cell death and growth can be cardiotoxic further supports our hypothesis. Understanding the role of resident and extracardiac progenitors in the pathogenesis of cardiomyopathies of different etiology will provide not only a better comprehension of cardiac homeostasis but will also open new avenues for therapeutic interventions. The progress toward effective myocardial regeneration based on exploiting the self-renewal potential of the myocardium and the systemic pool of cardiogenic cells should advance the likelihood of efficient cardioprotection and restoration of cardiac function.

Combination of Gefitinib and Pemetrexed Prevents the Acquisition of TKI Resistance in NSCLC Cell Lines Carrying EGFR-Activating Mutation

INTRODUCTION

Development of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors is a clinical issue in patients with epidermal growth factor receptor gene (EGFR)-mutated non-small cell lung cancer (NSCLC). The aim of this study was to investigate the potential of combining gefitinib and pemetrexed in preventing the acquisition of resistance to EGFR tyrosine kinase inhibitors in NSCLC cell lines harboring EGFR exon 19 deletion.

METHODS

The effect of different combinatorial schedules of gefitinib and pemetrexed on cell proliferation, cell cycle, apoptosis, and acquisition of gefitinib resistance in PC9 and HCC827 NSCLC cell lines and in PC9 xenograft models was investigated.

RESULTS

Simultaneous treatment with gefitinib and pemetrexed enhanced cell growth inhibition and cell death and prevented the appearance of gefitinib resistance mediated by T790M mutation or epithelial-to-mesenchymal transition (EMT) in PC9 and HCC827 cells, respectively. In PC9 cells and in PC9 xenografts the combination of gefitinib and pemetrexed, with different schedules, prevented gefitinib resistance only when pemetrexed was the first treatment, given alone or together with gefitinib. Conversely, when gefitinib alone was administered first and pemetrexed sequentially alternated, a negative interaction was observed and no prevention of gefitinib resistance was documented. The mechanisms of resistance that developed in vivo included T790M mutation and EMT. The induction of EMT was a feature of tumors treated with gefitinib when given before pemetrexed, whereas T790M was recorded only in tumors treated with gefitinib alone.

CONCLUSIONS

The combination of gefitinib and pemetrexed is effective in preventing gefitinib resistance; the application of intermittent treatments requires that gefitinib not be administered before pemetrexed.

Bioactive electrospun fibers of poly(glycerol sebacate) and poly(ε-caprolactone) for cardiac patch application

Scaffolds for cardiac patch application must meet stringent requirements such as biocompatibility, biodegradability, and facilitate vascularization in the engineered tissue. Here, a bioactive, biocompatible, and biodegradable electrospun scaffold of poly(glycerol sebacate)-poly(ε-caprolactone) (PGS-PCL) is proposed as a potential scaffold for cardiac patch application. The fibers are smooth bead free with average diameter = 0.8 ± 0.3 μm, mean pore size = 2.2 ± 1.2 μm, porosity = 62 ± 4%, and permeability higher than that of control biological tissue. For the first time, bioactive PGS-PCL fibers functionalized with vascular endothelial growth factor (VEGF) are developed, the approach used being chemical modification of the PGS-PCL fibers followed by subsequent binding of VEGF via amide bonding. The approach results in uniform immobilization of VEGF on the fibers; the concentrations are 1.0 μg cm(-2) for the PGS-PCL (H) and 0.60 μg cm(-2) for the PGS-PCL (L) samples. The bioactive scaffold supports the attachment and growth of seeded myogenic and vasculogenic cell lines. In fact, rat aortic endothelial cells also display angiogenic features indicating potential for the formation of vascular tree in the scaffold. These results therefore demonstrate the prospects of VEGF-functionalized PGS-PCL fibrous scaffold as promising matrix for cardiac patch application.

Titanium dioxide nanoparticles promote arrhythmias via a direct interaction with rat cardiac tissue

BACKGROUND

In light of recent developments in nanotechnologies, interest is growing to better comprehend the interaction of nanoparticles with body tissues, in particular within the cardiovascular system. Attention has recently focused on the link between environmental pollution and cardiovascular diseases. Nanoparticles <50 nm in size are known to pass the alveolar-pulmonary barrier, enter into bloodstream and induce inflammation, but the direct pathogenic mechanisms still need to be evaluated. We thus focused our attention on titanium dioxide (TiO₂) nanoparticles, the most diffuse nanomaterial in polluted environments and one generally considered inert for the human body.

METHODS

We conducted functional studies on isolated adult rat cardiomyocytes exposed acutely in vitro to TiO₂ and on healthy rats administered a single dose of 2 mg/Kg TiO₂ NPs via the trachea. Transmission electron microscopy was used to verify the actual presence of TiO₂ nanoparticles within cardiac tissue, toxicological assays were used to assess lipid peroxidation and DNA tissue damage, and an in silico method was used to model the effect on action potential.

RESULTS

Ventricular myocytes exposed in vitro to TiO₂ had significantly reduced action potential duration, impairment of sarcomere shortening and decreased stability of resting membrane potential. In vivo, a single intra-tracheal administration of saline solution containing TiO₂ nanoparticles increased cardiac conduction velocity and tissue excitability, resulting in an enhanced propensity for inducible arrhythmias. Computational modeling of ventricular action potential indicated that a membrane leakage could account for the nanoparticle-induced effects measured on real cardiomyocytes.

CONCLUSIONS

Acute exposure to TiO₂ nanoparticles acutely alters cardiac excitability and increases the likelihood of arrhythmic events.

Lung mesenchymal cells function as an inductive microenvironment for human lung cancer propagating cells†

OBJECTIVES

The aim of the present study was to characterize the biological properties and in vivo tumourigenic potential of mesenchymal cells (MCs) obtained from non-small-cell lung cancer (NSCLC) samples.

METHODS

NSCLC samples (53 adenocarcinomas and 24 squamous-cell carcinomas) surgically removed from 46 males and 31 females were processed to identify mesenchymal cells from human lung cancer (hLc-MCs). hLc-MCs were separated from neoplastic epithelial cells, expanded and extensively characterized in vitro. Subsequently, female BALB/c nude mice were subcutaneously injected with either 10(6) or 2.5 × 10(6) Calu-3 (human adenocarcinoma cell line able to reproducibly induce xenografted tumours) alone or in combination with equal doses of hLc-MCs. Control animals were injected with the two doses of hLc-MCs only.

RESULTS

Primary cultures of hLc-MCs were obtained from >80% of NSCLC specimens. The typical MCs immunophenotype was documented by the expression of CD90, CD105, CD73, CD13 and CD44 at fluorescence-activated cell sorting analysis. CD45, CD14, CD34 and epithelial antigens were negative while CD117 (c-kit) and CD133 (prominin) were partially expressed. Interestingly, nuclear transcription factors octamer-binding transcription factor 3/4 and sex determining region Y-box 2 involved in stemness, thyroid transcription factor 1 in bronchoalveolar commitment, and ETS1 in carcinogenesis, were expressed in hLc-MCs isolated from NSCLC. Specific conditioned media and cocultures confirmed the supportive role of hLc-MCs for cancer cells. In vivo experiments showed that at both doses Calu-3 xenografts doubled in size when hLc-MCs were coinjected. Cell tracking in xenografted tumours, by immunofluorescence combined with fluorescence in situ hybridization analysis, documented hX-chromosome-labelled, Calu-3-derived cytokeratin-positive adenocarcinoma structures surrounded by hLc-MCs.

CONCLUSIONS

Tumour-propagating cells require the inductive interaction of resident mesenchymal cells to foster lung cancer development.

[Familial hyperaldosteronism]

Primary aldosteronism is a disorder characterized by hypertension and hypokalemia due to aldosterone secretion out of renin-angiotensin control. It is generally caused by aldosterone-producing adenoma or adrenocortical hyperplasia but, in some cases, it is due to genetic alterations. Familial type I hyperaldosteronism is the result of anomalous regulation of aldosterone secretion from ACTH (which normally regulates cortisol synthesis). Aldosterone hypersecretion can be suppressed by exogenous glucocortcoids such as dexamethasone. This autosomal dominant disorder is caused by unequal cross-over between two genes with wide sequence homology: CYP11B1 and CYP11B2. The hybrid gene is the product of fusion between the ACTH-responsive regulatory portion of the 11b-hydroxylase gene (CYP11B1) and the coding region of the aldosterone synthase gene (CYP11B2). Familial type I hyperaldosteronism is a disease with incomplete penetration and variable expressivity, especially in relation to hypertension. The marked variability in hypertension severity can mirror an interaction between the hybrid gene and other hereditary factors involved in the regulation of blood pressure. Familial type II hyperaldosteronism is another autosomal dominant form of hyperaldosteronism due to aldosterone hyper-secretion not suppressible by dexamethasone. This disorder is unrelated to mutation of the hybrid gene. The genetic cause of type II hyperaldosteronism is presently unknown, but a genome-wide search has revealed that the disorder is linked with a locus on chromosome 7 in a region that corresponds to cytogenetic band 7p22.

A randomized study of methotrexate, bleomycin, hydroxyurea with versus without cisplatin in patients with previously untreated and recurrent squamous cell carcinoma of the head and neck

The value of a combination of methotrexate, bleomycin and hydroxyurea with vs. without cisplatin was randomly examined in 62 evaluable patients with previously untreated (44 patients) and recurrent (18 patients) squamous cell carcinoma of the head and neck. Methotrexate (30 mg/m2) and bleomycin (15 mg) were given intravenously weekly, hydroxyurea (1000 mg/m2) per os 3 times per week for 4 weeks. Cisplatin (60 mg/m2) was added on Day 1 every month. A higher overall response rate was observed with the cisplatin-containing regimen (66%, included 17% complete) as compared with 27% (3% complete) with the 3-drug combination (P value 0.0025). The cisplatin-containing regimen was more active in both previously untreated patient group and in the group recurrent patients. Toxicity was more pronounced in the cisplatin regimen and necessitated frequently reduced drug dosages. No survival difference was observed between the treatment groups. Median survival in previously untreated patients was 16.2 months and 7.2 months in patients who failed conventional local treatment. It is concluded that a cisplatin-containing regimen is more effective in advanced head and neck carcinoma than the same combination without cisplatin.

[High-dosage methylprednisolone as an antiemetic in cytostatic-induced vomiting]

The antiemetic efficacy of 375 mg methylprednisolone given as slow i.v. push injection was assessed in 27 tumor patients receiving strongly emetic cytostatic treatment. 13 of 27 patients were partially or completely protected from nausea and vomiting. Only minor side effects from methylprednisolone were observed: two patients complained of increased fatigue and four patients experienced facial rash with swelling 1 to 24 hours after the injection of methylprednisolone. High-dose methylprednisolone is an effective antiemetic treatment for patients receiving cancer chemotherapy.

[Prevention of cytostatic-related hair loss by hypothermia of a hairy scalp using a cooling cap]

82 patients treated with adriamycin alone or in combination with other cytostatic agents underwent scalp hypothermia by application of a gel cap. The cap ws applied 10 minutes before the injection of the drugs and maintained until 30 minutes after the administration of the chemotherapy. Prevention of hair loss was achieved in 47 patients (57%). The prophylaxis was successful in 16 out of 21 males (76%) compared with 31 out of 61 female patients (p less than 0.05). No statistically significant difference was found between patients receiving higher or lower doses of adriamycin or between patients wtih or without liver dysfunction. The tolerance of the gel cap was excellent; only one patient did not tolerate the cap because of anxiety during application.

[Nausea and vomiting during chemotherapy of malignant tumors]

Nausea and vomiting are frequent and unpleasant side effects of cancer chemotherapy. Current concepts of pathophysiology and clinical aspects of nausea and vomiting are reviewed. Individual and therapeutic factors are discussed which greatly modify the degree of vomiting. The commercially available antiemetics are tabulated and the individual classes of antiemetics are described. Finally, consideration is given to new approaches to the treatment of nausea and vomiting, including the search for new compounds and better use of currently available agents.

[Fat embolism syndrome without fractures]

Report on an 18-year-old patient who developed a respiratory distress syndrome after trauma without bone fractures and with only minimal soft tissue contusion. Twelve hours after the accident fever and dyspnea appeared, accompanied later by hemoptysis, microhematuria, a fall in hemoglobin and in platelet count, petechiae on the skin and in the conjunctiva, cotton-wool lesions in the retina and micronodular shadows in the lungs. Various pathogenetic mechanisms other than bone marrow fat embolism are discussed in the light of this case.