Preliminary investigation of blood vessel-derived acellular matrix for vascular graft application

Although autologous vascular grafts and artificial materials have been used for reconstruction of small diameter (<5mm) blood vessels, the poor availability of vessels and the occurrence of intimal hyperplasia and progressive atherosclerotic degeneration represent shortcomings of these vascular prostheses. Therefore, this preliminary study aimed to develop acellular matrix (AM)-based vascular grafts. Rat thoracic aortas were decellularized by means of a detergent-enzymatic treatment [1], whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Twenty male Lewis rats (8 week old) received either only AM and previously in vitro reendothelized AM as abdominal aorta Interposition grafts (about 2 cm). After 1 (n=10) and 3 (n=10) months from surgery, grafts were explanted and morphologically examined by scanning electron microscopy and Movat staining. The detergent enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. After 1 month from surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all the grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM pre-seeded with ECs could be a promising approach for the replacement of blood vessels

Alpha-melanocyte stimulating hormone (α-MSH): biology, clinical relevance and implication in melanoma

Abstract Alpha-melanocyte stimulating hormone (α-MSH) and its receptor, melanocortin 1 receptor (MC1R), have been proposed as potential target for anti-cancer strategies in melanoma research, due to their tissue specific expression and involvement in melanocyte homeostasis. However, their role in prevention and treatment of melanoma is still debated and controversial. Although a large body of evidence supports α-MSH in preventing melanoma development, some preclinical findings suggest that the α-MSH downstream signalling may promote immune escape and cancer resistance to therapy. Additionally, in metastatic melanoma both MC1R and α-MSH have been reported to be overexpressed at levels much higher than normal cells. Furthermore, targeted therapy (e.g. BRAF inhibition in BRAFV600E mutant tumours) has been shown to enhance this phenomenon. Collectively, these data suggest that targeting MC1R could serve as an approach in the treatment of metastatic melanoma. In this review, we explore the molecular biology of α-MSH with particular emphasis into its tumor-related properties, whilst elaborating the experimental evidence currently available regarding the interplay between α-MSH/MC1R axis, melanoma and antitumor strategies

Macrophage-Mediated Melanoma Reduction after HP-NAP Treatment in a Zebrafish Xenograft Model

The Helicobacter pylori Neutrophil Activating Protein (HP-NAP) is endowed with immunomodulatory properties that make it a potential candidate for anticancer therapeutic applications. By activating cytotoxic Th1 responses, HP-NAP inhibits the growth of bladder cancer and enhances the anti-tumor activity of oncolytic viruses in the treatment of metastatic breast cancer and neuroendocrine tumors. The possibility that HP-NAP exerts its anti-tumor effect also by modulating the activity of innate immune cells has not yet been explored. Taking advantage of the zebrafish model, we examined the therapeutic efficacy of HP-NAP against metastatic human melanoma, limiting the observational window to 9 days post-fertilization, well before the maturation of the adaptive immunity. Human melanoma cells were xenotransplanted into zebrafish embryos and tracked in the presence or absence of HP-NAP. The behavior and phenotype of macrophages and the impact of their drug-induced depletion were analyzed exploiting macrophage-expressed transgenes. HP-NAP administration efficiently inhibited tumor growth and metastasis and this was accompanied by strong recruitment of macrophages with a pro-inflammatory profile at the tumor site. The depletion of macrophages almost completely abrogated the ability of HP-NAP to counteract tumor growth. Our findings highlight the pivotal role of activated macrophages in counteracting melanoma growth and support the notion that HP-NAP might become a new biological therapeutic agent for the treatment of metastatic melanomas

Blood Vessel-Derived Acellular Matrix for Vascular Graft Application

To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm) blood vessels, this study aimed to develop acellular matrix- (AM-) based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old) received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1 cm). The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels

Melanoma in Adolescents and Young Adults: Evaluation of the Characteristics, Treatment Strategies, and Prognostic Factors in a Monocentric Retrospective Study

The "Veneto Cancer Registry" records melanoma as the most common cancer diagnosed in males and the third common cancer in females under 50 years of age in the Veneto Region (Italy). While melanoma is rare in children, it has greater incidence in adolescents and young adults (AYA), but literature offers only few studies specifically focused on AYA melanoma. The aim of this study was to describe the characteristics, surgical treatment, and prognosis of a cohort of AYA melanoma in order to contribute to the investigation of this malignancy and provide better patient care. This retrospective cohort study included 2,752 Caucasian patients (702 AYA and 2,050 non-AYA patients) from the Veneto Region who were over 15 years of age at diagnosis, and who received diagnosis and/or treatment from our institutions between 1998 and 2014. Patients were divided in adolescents and youth (15-25 years), young adults (26-39 years) and adults (more than 39 years) for the analysis. We found statistically significant differences in gender, primary site, Breslow thickness, ulceration, pathologic TNM classification (pTNM) stage and tumor subtype among the age groups. Disease-specific survival and disease-free survival were also different among the age groups. Our findings suggest that the biological behavior of melanoma in young people is different to that in adults, but not such as to represent a distinct pathological entity. Additional and larger prospective studies should be performed to better evaluate potential biological and cancer-specific differences between AYAs and the adult melanoma population

Representative images of α-amilase staining among gastroesophageal-mucosa samples.

<p>Examples of oxyntic mucosa (A), gastroesophageal mucosa with BE (B), BE (C), and EAC (D) showing a negative/weak immunoreaction. Pancreatic acinar cell metaplasia of the oxyntic mucosa was observed at higher incidence in the treated group and was strongly positive for α-amylase (E and F). Both H&E and the corresponding IHC staining are shown. Original magnification 20X, 40X.</p

Incidence of pathological findings observed in the animals under PPI treatment and in animals under placebo that reached the end of the experiments.

<p>Data expressed as n(%). ^#Fisher Test. A p-value<0.05 is considered statistically significant. BE = Barrett esophagus.</p><p>Incidence of pathological findings observed in the animals under PPI treatment and in animals under placebo that reached the end of the experiments.</p

Representative images of esophageal lesions (H&E stain).

<p>(A) regenerative and (B and C) hyperplastic lesions within the esophageal mucosa. Original magnification 30X (A, B and C).</p

Barrett’s related lesions observed in the murine model (H&E stain).

<p>(A) multi-layered epithelium; (B) Barrett’s esophagus; (C) esophagistis <i>cystica profunda</i>; (D and E) esophageal glandular neoplasia; and (F) squamous cell neoplasia. Original magnification 40X (A), 30X (B), 20X (C–F).</p