Costanza Lagrasta

Nerve growth factor promotes cardiac repair following myocardial infarction

Rationale: Nerve growth factor (NGF) promotes angiogenesis and cardiomyocyte survival, which are both desirable for postinfarction myocardial healing. Nonetheless, the NGF potential for cardiac repair has never been investigated. Objective: To define expression and localization of NGF and its high-affinity receptor TrkA (tropomyosin-related receptor A) in the human infarcted heart and to investigate the cardiac roles of both endogenous and engineered NGF using a mouse model of myocardial infarction (MI). Methods and Results: Immunostaining for NGF and TrkA was performed on heart samples from humans deceased of MI or unrelated pathologies. To study the post-MI functions of endogenous NGF, a NGF-neutralizing antibody (Ab-NGF) or nonimmune IgG (control) was given to MI mice. To investigate the NGF therapeutic potential, human NGF gene or control (empty vector) was delivered to the murine periinfarct myocardium. Results indicate that NGF is present in the infarcted human heart. Both cardiomyocytes and endothelial cells (ECs) possess TrkA, which suggests NGF cardiovascular actions in humans. In MI mice, Ab-NGF abrogated native reparative angiogenesis, increased EC and cardiomyocyte apoptosis and worsened cardiac function. Conversely, NGF gene transfer ameliorated EC and cardiomyocyte survival, promoted neovascularization and improved myocardial blood flow and cardiac function. The prosurvival/proangiogenic Akt/Foxo pathway mediated the therapeutic benefits of NGF transfer. Moreover, NGF overexpression increased stem cell factor (the c-kit receptor ligand) expression, which translated in higher myocardial abundance of c-kitpos progenitor cells in NGF-engineered hearts. Conclusions: NGF elicits pleiotropic beneficial actions in the post-MI heart. NGF should be considered as a candidate for therapeutic cardiac regeneration.

End-stage cardiac failure in humans is coupled with the induction of proliferating cell nuclear antigen and nuclear mitotic division in ventricular myocytes.

Proliferating cell nuclear antigen (PCNA) is a late growth-regulated gene that is expressed at the G1-S boundary of the cell cycle and is required for DNA synthesis and cell proliferation. Since quantitative results suggest that myocyte hyperplasia occurs in the decompensated human heart, we postulated that induction of the PCNA gene may be present in the failing heart in humans. PCNA protein was detected in myocardial samples obtained from the left and right ventricles of patients with congestive heart failure. Endomyocardial biopsies collected from donor subjects were used as control tissue. The percentage of positively stained myocyte nuclei in the ventricles was established by using PCNA monoclonal antibody and the immunoperoxidase technique. The localization of PCNA in myocytes was confirmed by alpha-sarcomeric actin antibody staining. PCNA labeling was present in left ventricular myocytes of 29 of the 32 hearts examined. In the right ventricle, 24 of the 29 samples showed positive staining. In a subset of 25 patients, the percentage of PCNA-labeled myocyte nuclei was measured and found to constitute 49 +/- 22% of left ventricular myocytes. A similar analysis for the right ventricle, conducted in 21 patients, showed that 49 +/- 19% of the myocyte nuclei exhibited PCNA protein. In addition, mitotic figures in myocytes were documented. A quantitative analysis of this cellular process revealed that 11 myocyte nuclei per 1 million cells exhibited mitotic images in chronic heart failure. Immediately after myocardial infarction, two cells per million showed mitotic division, and this phenomenon was restricted to the region adjacent to the necrotic tissue. No PCNA labeling or nuclear mitotic images were detected in the ventricular myocardium of control subjects. Thus, the observation that diffuse PCNA labeling and myocyte mitotic division are present in hearts with end-stage failure strongly suggests that adult ventricular myocytes are not terminally differentiated cells and that myocyte cellular hyperplasia may constitute a growth reserve mechanism of the diseased heart.

Comparison of HER2 status in primary and paired metastatic sites of gastric carcinoma

Background:Trastuzumab has recently shown efficacy in the treatment of HER2-positive advanced gastric adenocarcinoma. Although antibody-based therapies target the metastatic disease, HER2 status is usually evaluated in the primary tumour because metastatic sites are rarely biopsied. The aim of this study was to compare HER2 status in primary and paired metastatic sites of gastric adenocarcinoma.Methods:The HER2 status was assessed by fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC) in 72 secondary lesions of gastric adenocarcinoma and in the corresponding primary tumours.Results:Concordance of FISH results, evaluable in 68 primary and matched metastatic sites, was 98.5%. Concordance of IHC results, available in 39 of the 72 paired cases, was 94.9%. Only one case showed discordance between primary tumour and metastasis, being negative by both IHC and FISH in the primary and showing HER2 overexpression and amplification in the corresponding pancreatic lymph node metastasis.Conclusion:The high concordance observed between HER2 results obtained by both IHC and FISH on primary tumours and corresponding metastases suggests that in gastric cancer HER2 status is maintained in most cases unchanged during the metastatic process.

Genetic deletion of the p66 Shc adaptor protein protects from angiotensin II-induced myocardial damage

Angiotensin II (Ang II), acting through its G protein–coupled AT1 receptor (AT1), contributes to the precocious heart senescence typical of patients with hypertension, atherosclerosis, and diabetes. AT1 was suggested to transactivate an intracellular signaling controlled by growth factors and their tyrosin-kinase receptors. In cultured vascular smooth muscle cells, this downstream mechanism comprises the p66Shc adaptor protein, previously recognized to play a role in vascular cell senescence and death. The aim of the present study was 2-fold: (1) to characterize the cardiovascular phenotype of p66Shc knockout mice (p66Shc−/−), and (2) to test the novel hypothesis that disrupting the p66Shc might protect the heart from the damaging action of elevated Ang II levels. Compared with wild-type littermates (p66Shc+/+), p66Shc−/− showed similar blood pressure, heart rate, and left ventricular wall thickness. However, cardiomyocyte number was increased in mutant animals, indicating a condition of myocardial hyperplasia. In p66Shc+/+, infusion of a sub-pressor dose of Ang II (300 nmol/kg body weight [BW] daily for 28 days) caused left ventricular hypertrophy and apoptotic death of cardiomyocytes and endothelial cells. In contrast, p66Shc−/− were resistant to the proapoptotic/hypertrophic action of Ang II. Consistently, in vitro experiments showed that Ang II causes apoptotic death of cardiomyocytes isolated from p66Shc+/+ hearts to a greater extent as compared with p66Shc−/− cardiomyocytes. Our results indicate a fundamental role of p66Shc in Ang II–mediated myocardial remodeling. In perspective, p66Shc inhibition may be envisioned as a novel way to prevent the deleterious effects of Ang II on the heart.

Human cardiac and bone marrow stromal cells exhibit distinctive properties related to their origin

AIMS Bone marrow mesenchymal stromal cell (BMStC) transplantation into the infarcted heart improves left ventricular function and cardiac remodelling. However, it has been suggested that tissue-specific cells may be better for cardiac repair than cells from other sources. The objective of the present work has been the comparison of in vitro and in vivo properties of adult human cardiac stromal cells (CStC) to those of syngeneic BMStC. METHODS AND RESULTS Although CStC and BMStC exhibited a similar immunophenotype, their gene, microRNA, and protein expression profiles were remarkably different. Biologically, CStC, compared with BMStC, were less competent in acquiring the adipogenic and osteogenic phenotype but more efficiently expressed cardiovascular markers. When injected into the heart, in rat a model of chronic myocardial infarction, CStC persisted longer within the tissue, migrated into the scar, and differentiated into adult cardiomyocytes better than BMStC. CONCLUSION Our findings demonstrate that although CStC and BMStC share a common stromal phenotype, CStC present cardiovascular-associated features and may represent an important cell source for more efficient cardiac repair.

Cellular basis of wall remodeling in long-term pressure overload-induced right ventricular hypertrophy in rats.

To determine the effects of long-term pressure overload on the structural mechanisms implicated in wall remodeling of the right ventricle, a mild pulmonary artery banding was applied to rats approximately 2 months old, and the animals were killed 150 days later. The surgical procedure resulted in a 60% reduction in the cross-sectional area of the constricted vessel and a 52% increase in the weight of the right ventricle. The hypertrophic myocardial response was associated with an elevation in right ventricular systolic pressure (from 33 ± 11 mm Hg to 71 ± 12 mm Hg), right ventricular end-diastolic pressure (from 3 ± 1 mm Hg to 10 ± 3 mm Hg), and central venous pressure (from 2± 0.2 mm Hg to 10 ± 3 mm Hg). The 76% increase in wall thickness after pulmonary artery stenosis was the result of a 24% lateral expansion of cardiac muscle cells and a 44% increase in the number of myocytes across the ventricular wall. The intermyocyte distance was also increased by 22%. These cellular adaptations occurred with no alterations in total myocyte length, average sarcomere length, and volume composition of the myocardium. Ventricular wall area was decreased by 14%, which suggests a small reduction in chamber volume. Myocyte growth was accompanied by proportional expansions of mitochondrial and myofibrillar components, so that the ratio of mitochondria to myofibrils in the cytoplasm remained essentially constant. In conclusion, ventricular remodeling in this model of chronic pressure hypertrophy is characterized by increases in cellular diameter and number that would both tend to decrease the magnitude of systolic and diastolic stresses on a per cell basis and thus improve the myocardial response to a prolonged and sustained mechanical load.

Cardiac hypertrophy and microvascular deficit in kinin B2 receptor knockout mice.

Abstract—Experimental and clinical evidence suggests kinin involvement in adaptive myocardial growth. Kinins are growth-inhibitory to cardiomyocytes. Knockout of kinin B2 receptor (B2R) signaling causes dilated and failing cardiomyopathy in 129/J mice, and a 9-bp deletion polymorphism of human B2R is associated with reduced receptor expression and exaggerated left ventricular growth response to physical stress. We reasoned that genetic background and aging may significantly influence the impact of B2R mutation on cardiac phenotype. The theory was challenged in C57BL/6 mice, a strain that naturally differs from the 129/J strain, carrying 1 instead of 2 renin genes. C57BL/6 B2R knockouts (B2R-KO) showed higher blood pressure and heart rate levels (P <0.05) compared with wild-type controls (WT) at all ages examined. At 12 months, left ventricular contractility and diastolic function were mildly altered (P <0.05) and histological and morphological analyses revealed ventricular hypertrophy and cardiomyocyte enlargement in B2R-KO (P <0.01). Reparative fibrosis was enhanced by 208% and capillary density reduced by 38% (P <0.01). Functional and structural alterations induced by B2R deletion in C57BL/6 mice were less severe than those reported previously in the 129/J strain. We conclude that interaction of B2R signaling with other genetic determinants influences aging-related changes in myocardial structure and function. These findings may help us understand the role of kinins in the development of cardiac failure.

PTEN status in advanced colorectal cancer treated with cetuximab

Background:Loss of phosphatase and tensin homologue deleted in chromosome 10 (PTEN) function in advanced colorectal cancer (CRC) may represent one of the resistance mechanisms to cetuximab by interfering with the epidermal growth factor receptor signal transduction pathway.Methods:PTEN expression tested by indirect immunofluorescence was evaluated both on primary (n=43) and on metastatic (n=24) sites in CRC patients treated with cetuximab.Results:The loss of PTEN expression tested on metastatic sites was negatively associated with response (100% progressive disease (PD) in PTEN-negative cases vs 30% PD in PTEN-positive cases; P<0.05), PFS (0.8 vs 8.2 months; P<0.001) and OS (2.9 vs 14.2 months; P<0.001).Conclusion:A potential role of PTEN in the anti-tumour activity of cetuximab could be hypothesised.

Predictors of gefitinib outcomes in advanced non-small cell lung cancer (NSCLC): study of a comprehensive panel of molecular markers.

A number of different clinical characteristics and molecular markers related to epidermal growth factor receptor (EGFR) activation have been reported to singly correlate with therapeutic activity of EGFR tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC). This study was designed to evaluate the predictive value on gefitinib outcomes of a comprehensive panel of molecular parameters in advanced NSCLC patients. EGFR and K-ras mutations were detected by direct sequencing on tumor DNA from paraffin embedded samples. EGFR and HER2 gene copy number was assessed by FISH. EGFR protein expression was quantified by immunohistochemistry. EGFR gene intron 1 polymorphism was assessed on genomic DNA isolated from venous whole blood samples. Ninety-one patients were prospectively enrolled and the overall gefitinib response rate was 18.7% (2 complete and 15 partial responses). Sex (p=0.005), non-smoking status (p=0.010), skin toxicity (p=0.020), EGFR gene mutations (p<0.001) and EGFR FISH positivity (p=0.016) were found to be associated with gefitinib response. K-ras mutation was detected in only seven non-responder patients. The median overall survival was of 10 months. Only non-smoking status and EGFR intron 1 polymorphism showed a statistically significant correlation with survival (p=0.031 and 0.044, respectively). In conclusion, we have confirmed the role of EGFR gene mutation as predictor of response to EGFR TKIs. Moreover, EGFR gene copy number and, potentially, also EGFR intron 1 polymorphism could aid in better prediction of EGFR TKI responsiveness in advanced NSCLC.

Comparison Between Epidermal Growth Factor Receptor (EGFR) Gene Expression in Primary Non-small Cell Lung Cancer (NSCLC) and in Fine-Needle Aspirates from Distant Metastatic Sites

Purpose: Epidermal growth factor receptor (EGFR) gene copy number obtained by fluorescence in situ hybridization (FISH) has been recently found to predict treatment outcome in non-small cell lung cancer (NSCLC) patients receiving EGFR tyrosine kinase inhibitors. However, it is still unknown whether EGFR status differs in metastases compared with primary NSCLC. In all studies FISH have been performed on histologic material. The possibility to perform FISH analysis on cytologic material obtained by fine-needle aspiration from superficial and visceral metastases would allow us to know the real EGFR status avoiding invasive diagnostic procedures. Methods: EGFR gene copy number was analyzed by FISH on fine-needle aspirates obtained from 31 patients with metastatic NSCLC and the results were compared with those obtained on corresponding paraffin histologic sections from the primary tumor. Results: The feasibility of EGFR FISH on cytology was 90% (28 of 31 patients). EGFR FISH was positive in 61% (17 of 28 patients) of the metastases and in 36% (10 of 28 patients) of the primary tumors. Nine of the 28 cases (32%) were EGFR positive on both primary tumor and metastatic site and 10 (36%) were negative on both primary tumor and metastasis. Nine of the 28 cases (32%) showed discordance of primary tumor versus metastasis (McNemar test; p = 0.041). Conclusions: EGFR FISH can be reliably assessed on fine-needle aspirates obtained from NSCLC metastases. We found that EGFR gene copy number is discordant between primary NSCLC and the corresponding distant metastatic sites in a significant proportion of cases. These findings should be considered in future studies designed to elucidate the predictive role of EGFR FISH in NSCLC.