miRNA-221 and miRNA-483-3p Dysregulation in Esophageal Adenocarcinoma.

Alterations in microRNA (miRNA) expression have been reported in different cancers. We assessed the expression of 754 oncology-related miRNAs in esophageal adenocarcinoma (EAC) samples and evaluated their correlations with clinical parameters. We found that miR-221 and 483-3p were consistently upregulated in EAC patients vs. controls (Wilcoxon signed-rank test: miR-221 p < 0.0001; miR-483-3p p < 0.0001). Kaplan-Meier analysis showed worse cancer-related survival among all EAC patients expressing high miR-221 or miR-483-3p levels (log-rank p = 0.0025 and p = 0.0235, respectively). Higher miR-221 or miR-483-3p levels also correlated with advanced tumor stages (Mann-Whitney p = 0.0195 and p = 0.0085, respectively), and overexpression of miR-221 was associated with worse survival in low-risk EAC patients. Moreover, a significantly worse outcome was associated with the combined overexpression of miR-221 and miR-483-3p (log-rank p = 0.0410). To identify target genes affected by miRNA overexpression, we transfected the corresponding mimic RNA (miRVANA) for either miR-221 or miR-483-3p in a well-characterized esophageal adenocarcinoma cell line (OE19) and performed RNA-seq analysis. In the miRNA-overexpressing cells, we discovered a convergent dysregulation of genes linked to apoptosis, ATP synthesis, angiogenesis, and cancer progression, including a long non-coding RNA associated with oncogenesis, i.e., MALAT1. In conclusion, dysregulated miRNA expression, especially overexpression of miR-221 and 483-3p, was found in EAC samples. These alterations were connected with a lower cancer-specific patient survival, suggesting that these miRNAs could be useful for patient stratification and prognosis.

Involvement of miR-30a-5p and miR-30d in Endothelial to Mesenchymal Transition and Early Osteogenic Commitment under Inflammatory Stress in HUVEC.

The endothelial to mesenchymal transition (End-MT) can be associated with vascular calcification, by providing mesengenic progenitors. In this study, we investigated a link between End-MT and the osteogenic process and explored the involvement of miR-30a-5p and miR-30d as potential regulators of these processes. End-MT was induced in Human Umbilical Vein Endothelial Cells (HUVEC) through transforming growth factor-ß1 (TGF-ß1), TGFß-3 and tumor necrosis factor-α (TNF-α), for 24 h and 6 days. End-MT mediators, mesenchymal and osteo/chondrogenic markers were analyzed through Real-Time PCR, immunofluorescence, flow cytometry and Western Blot. miR-30a-5p and miR-30d over-expression was carried out in HUVEC to explore their effects on End-MT and osteogenic differentiation. HUVEC at 24 h and 6 days gained mesenchymal morphology markers, including matrix metalloproteinase 9 (MMP-9), SLUG, VIMENTIN and α-smooth muscle actin (α-SMA), and a significant migratory potential, notably with TNF-α. After 6 days, the osteo/chondrogenic markers runt-related transcription factor 2 (RUNX-2) and SRY box transcription factor 9 (SOX-9) were upregulated. At this time point, miR-30a-5p and miR-30d decreased. Over-expression of miR-30a-5p and miR-30d affected End-MT mediators and the osteogenic potency in HUVEC, by reducing SLUG, VIMENTIN and RUNX-2. Our data suggest that End-MT represents a key link between inflammation and vascular calcification. Further, miR-30a-5p and miR-30d can regulate both the End-MT and the osteogenic processes, prompting future studies for exploring their potential use as therapeutic targets or biomarkers in vascular diseases.

Sirolimus-eluting stents: opposite in vitro effects on the clonogenic cell potential on a long-term exposure.

We evaluated the long-term effects of sirolimus on three different cell in vitro models, cultured in physiological conditions mimicking sirolimus-eluted stent, in order to clarify the effectiveness of sirolimus in blocking cell proliferation and survival. Three cells lines (WPMY-1 myofibroblasts, HT-29 colorectal adenocarcinoma, and U2OS osteosarcoma) were selected and growth in 10 ml of Minimum Essential Medium for 5 weeks with serial dilutions of sirolimus. The number of colonies and the number of cells per colony were counted. As main result, the number of WPMY-1 surviving colonies increased in a dose-dependent manner when treated with sirolimus (p = 0.0011), while the number of U2OS colonies progressively decreased (p = 0.0011). The clonal capacity of HT-29 was not modified by the exposure to sirolimus (p = 0.6679). In conclusion sirolimus showed the well-known cytostatic effect, but with an effect on clonogenic potential different among the different cell types. In the practice, the plaque typology and composition may influence the response to sirolimus and thus the effectiveness of eluted stent.

Different histological types of active intraplaque calcification underlie alternative miRNA-mRNA axes in carotid atherosclerotic disease.

Arterial calcification is an actively regulated process, with different morphological manifestations. Micro-RNAs emerged as potential regulators of vascular calcification; they may become novel diagnostic tools and be used for a finest staging of the carotid plaque progression. The present study aimed at characterizing the different miRNA-mRNA axes in carotid plaques according to their histological patterns of calcification. Histopathological analysis was performed on 124 retrospective carotid plaques, with clinical data and preoperatory angio-CT. miRNA analysis was carried out with microfluidic cards. Real-time PCR was performed for selected miRNAs validation and for RUNX-2 and SOX-9 mRNA levels. CD31, CD68, SMA, and SOX-9 were analyzed by immunohistochemistry. miRNA levels on HUVEC cells were analyzed for confirming results under in vitro osteogenic conditions. Histopathological analysis revealed two main calcification subtypes of plaques: calcific cores (CC) and protruding nodules (PN). miRNA array and PCR validation of miR-1275, miR-30a-5p, and miR-30d indicated a significant upregulation of miR-30a-5p and miR-30d in the PN plaques. Likewise, the miRNA targets RUNX-2 and SOX-9 resulted poorly expressed in PN plaques. The inverse correlation between miRNA and RUNX-2 levels was confirmed on osteogenic-differentiated HUVEC. miR-30a-5p and miR-30d directly correlated with calcification extension and thickness at angio-CT imaging. Our study demonstrated the presence of two distinct morphological subtypes of calcification in carotid atheromatous plaques, supported by different miRNA signatures, and by different angio-CT features. These results shed the light on the use of miRNA as novel diagnostic markers, suggestive of plaque evolution.

Immunomorphology and molecular biology of mixed primary liver cancers: is Nestin a marker of intermediate-cell carcinoma?

AIMS: Primary mixed liver cancers (PLCs), combined hepatocellular-cholangiocellular (cHCC-CC) and intermediate-cell carcinomas are rare tumours characterised by different molecular mechanisms. Nestin is a marker of progenitor cells with a promising application in human tumours. The aims of the present paper are (i) to determine the expression of Nestin in mixed PLCs; and (ii) to correlate the PLC immunoprofile with the gene expression in each tumour component. METHODS AND RESULTS: We selected 28 mixed PLCs, 13 (46.4%) cHCC-CC and 15 (53.6%) intermediate-cell carcinomas. The immunohistochemistry panel consisted of keratin 7, keratin 19, CD56 and Nestin. Next-generation sequencing analysis was performed on 17 cases (27 specimens) using a multi-gene custom panel. The differentiated HCC and CC components of cHCC-CC were negative for Nestin in all cases. The intermediate areas of cHCC-CC were immunoreactive for Nestin in 92.3% of cases, for CD56 in 76.9% and for K7/K19 in all cases. The immunoprofile of the intermediate-cell carcinomas showed 73.3% of cases positive for Nestin and 66.7% for CD56. TP53 and TERT were the most frequently mutated genes (31.3% and 17.6% of samples, respectively). Mutations were also found in IDH1, IDH2, PIK3CA and NRAS genes. Intermediate and HCC areas of cHCC-CC seemed to share the same mutational profile, and both harboured different mutations than the CC component. CONCLUSIONS: According to our preliminary data, Nestin was not expressed by hepatocellular or cholangiocellular-cell components, but was expressed by most of the intermediate cells in PLCs, and therefore could be considered in the differential diagnosis of PLCs, together with mutational profile.

Pathobiological and Radiological Approach For Hepatocellular Carcinoma Subclassification.

Many advances have been made in the imaging diagnosis and in the histopathological evaluation of HCC. However, the classic imaging and histopathological features of HCC are still inadequate to define patient's prognosis. We aimed to find the link between new proposed morphovascular patterns of hepatocellular carcinoma (HCC) and magnetic resonance imaging (MRI) features to identify pre-operatory markers of biologically aggressive HCC. Thirty-nine liver nodules in 22 patients were consecutively identified. Histopathological analysis and immunohistochemistry for CD34 and Nestin were performed to identify the four different HCC morphovascular patterns. MRI was performed using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid. Three out of four morphovascular HCC patterns showed peculiar MRI features: in particular Pattern D (solid aggressive HCCs with CD34+/Nestin+ new-formed arteries) were isointense on T1-WI in 83% of cases and hyperintense on T2-WI in 50%. Five histologically-diagnosed HCC were diagnosed as non-malignant nodules on MRI due to their early vascularization and low aggressiveness (Pattern A). The comparison between histology and MRI confirms that a subclassification of HCC is possible in a pre-operatory setting. MRI seems to reinforce once more the identity of the different morphovascular HCC patterns and the possibility to pre-operatively identify HCCs with features of biological aggressiveness.

Genomic profiles of primary and metastatic esophageal adenocarcinoma identified via digital sorting of pure cell populations: results from a case report.

BACKGROUND: We report on a female patient who underwent primary radical resection for a stage 2B Her-2-positive Barrett's-type esophageal adenocarcinoma (EAC). Despite Her-2 targeted therapy, her disease recurred and required repeated metastectomies. CASE PRESENTATION: Digital cell sorting and targeted sequencing of cancer sub-clones from EAC and metastases revealed a completely mutated TP53, whereas the sorted stromal cells were wild-type. Her-2 amplification was significantly lower in the metastases when the patient became therapy-resistant. CONCLUSIONS: The mechanism of therapy resistance illustrated by this case could only be detected through accurate analysis of tumor sub-populations. Investigating tumor sub-populations of recurrent disease is important for adjusting therapy in recurrent EAC.

Tissue miRNA 483-3p expression predicts tumor recurrence after surgical resection in histologically advanced hepatocellular carcinomas.

The choice of surgical treatment for hepatocellular carcinoma (HCC) depends on several prognostic variables, among which histological features, like microvascular invasion and tumor grade, are well established. This study aims to identify the tissue miRNAs predictive of recurrence after liver resection in "histologically advanced" HCC. We selected 54 patients: 15 retrospective resected patients without recurrence (group A), 19 retrospective resected patients with HCC recurrence (group B), and 20 prospective patients (group C), with 4 recurrence cases. All selected HCC were "histologically advanced" (high Edmondson grade and/or presence of microvascular invasion). A wide spectrum of miRNAs was studied with TaqMan Human microRNA Arrays; qRT-PCR assays were used to validate results on selected miRNAs; immunohistochemistry for IGF2 was applied to study the mechanism of miR-483-3p. As a result, a significant differential expression between group A and B was found for 255 miRNAs. Among them we selected miR-483-3p and miR-548e (P<0.001). As a single variable (group C), HCC with miR-483-3p downregulation (mean fold increase 0.21) had 44.4% of recurrence cases; HCC with miR-483-3p upregulation (mean fold increase 5.94) showed no recurrence cases (P=0.011). At immunohistochemistry (group C), the HCC with loss of cytoplasmic IGF2 expression showed a down-regulation of miR-483-3p (fold increase 0.57). In conclusion, in patients with "histologically advanced" HCC, the analysis of specific tissue miRNAs (particularly miR-483-3p) could help identify the recurrence risk and choose which treatment algorithm to implement (follow-up, resection or transplantation). This could have an important impact on patient survival and transplantation outcome, improving organ allocation.

From large to small: the immunohistochemical panel in the diagnosis of early hepatocellular carcinoma.

AIMS: The aims of this study were to: validate the use of the immunohistochemical (IHC) markers glutamine synthetase (GS), glypican-3 (GPC3), heat shock protein-70 (HSP70) and enhancer of zeste homologue 2 (EZH2) in liver biopsies for the differential diagnosis between small hepatocellular carcinoma (HCC) and non-neoplastic liver nodules, with special attention to <10-mm nodules; and assess the actual sensitivity and specificity of the single markers, and their combination, in needle biopsies. METHODS AND RESULTS: One hundred liver nodules, i.e. 66 HCCs and 34 non-neoplastic nodules, were prospectively collected from 43 consecutive orthotopic liver transplantation patients, and subjected to 'backtable' needle biopsies directly on surgical specimens. IHC evaluation was semi-automatically performed with a Benchmark Ultra immunostainer. The morphological and IHC diagnosis in surgical specimens was considered to be the gold standard. GS, GPC3, HSP70 and EZH2 showed 16.6%, 10.7%, 28.8% and 62.1% decreases in sensitivity, respectively, from surgical specimen to needle biopsy. Higher decreases were observed in <10-mm nodules. In 18 HCCs with no morphological diagnostic features of malignancy in biopsies, GPC3 or GS were positive in 16; in seven HCCs, neither morphology nor IHC evaluation ruled out the differential diagnosis made on the basis of needle biopsy. CONCLUSIONS: We present for the first time a direct comparison between surgical specimens and needle biopsies to confirm the usefulness and reproducibility of the most widely used antibodies for the diagnosis of small liver nodules. Our results support the use of IHC evaluation in biopsies for the diagnosis of small liver lesions, although the IHC panel could also give negative results in the presence of obvious HCC, and the possibility of false positives should always be considered.

miRNA Signature of Hepatocellular Carcinoma Vascularization: How the Controls Can Influence the Signature.

BACKGROUND: miRNA deregulation and vascular modifications constitute promising predictors in the study of hepatocellular carcinoma (HCC). In the literature, the relative miRNA abundance in HCC is usually determined using as control non-matched tumoral tissue, healthy liver, or cirrhotic liver. However, a common standard RNA control for the normalization toward the tissue gene expression was not settled yet. AIM: To assess the differences existing in the quantitative miRNA gene expression in HCC on tissue according to two different liver controls. METHODS: A wide array of miRNAs was analyzed on 22 HCCs arisen in cirrhotic and non-cirrhotic livers by means of microfluidic cards. Control samples included total RNA extracted from healthy and cirrhotic livers. Immunohistochemistry for CD34 and Nestin was performed to assess the pattern of intratumoral vascular modifications. RESULTS: Six miRNAs were deregulated in HCCs using either controls: miR-532, miR-34a, miR-93, miR-149#, miR-7f-2#, and miR-30a-5p. Notably, the miRNA expression changed significantly between HCCs arisen in cirrhotic and non-cirrhotic livers, according to the control used for normalization. Different miRNA profiles were found also in HCCs with different vascular patterns, according to the control used for normalization. CONCLUSIONS: Our data confirm that the choice of the methodology, and particularly the control used for normalization, represents the main concern in miRNA evaluation, particularly in a heterogeneous model such as liver pathology. Still we observed the deregulation of some common miRNAs as promising in HCC cancerogenesis and progression. A standardized control will be a crucial achievement to compare miRNA expression among different laboratories.

Relationship between Calcification and Vulnerability of the Carotid Plaques.

BACKGROUND: Carotid plaques with a high degree of calcification are usually considered at low embolic risk. However, since a precise evaluation of the extent of calcification is not possible preoperatively through duplex ultrasound and postoperatively by conventional histological examination due to the decalcification process, the relationship between the amount of calcium involvement and plaque vulnerability has not been evaluated yet. This study aims to correlate the extent of carotid plaque calcification with clinical, radiological, and histological complications. METHODS: Symptomatic and asymptomatic consecutive patients submitted to carotid endarterectomy between January to December 2014 were included in the study. The amount of carotid calcification was assessed at preoperative computed tomography (CT) through measurement of thickness and circumferential calcium extension and graded from 1 to 8 accordingly (Babiarz classification). Patients were then categorized into 2 groups (low-level group: grade 1-5; high-level group: grade 6-8) and correlated with clinical characteristics and ipsilateral cerebral ischemic lesions at CT. Vulnerability of the plaque was assessed histologically according with American Heart Association (AHA) Classification. Results were overall blindly correlated. RESULTS: One hundred five patients (81% male; age: 73 ± 8 years) were enrolled in the study. Forty (38%) were symptomatic and 43 (40%) had an ipsilateral focal lesion at preoperative cerebral CT. Thirty-six (38%) patients had high-level carotid calcification degree at CT scan. At histological analysis, 56 (56%) plaques were considered complicated (AHA type VI). Patients with high-level and low-level carotid calcification had similar epidemiological risk factors, preoperative neurological symptoms, and histological complications (17% vs. 15%, P = 0.76 and 50% vs. 55%, P = 0.62, respectively). The high-level calcification group showed a significantly higher incidence of ipsilateral cerebral lesions at preoperative CT (56% vs. 32%, P = 0.01). CONCLUSIONS: A high level of calcification of the carotid plaque is not necessarily associated with lower vulnerability: the incidence of preoperative neurological symptoms and histological complications is similar in patients with and without extensive carotid plaque calcification. Cerebral ischemic lesions may be even more frequent in the presence of highly calcified plaques.

The study of calcified atherosclerotic arteries: an alternative to evaluate the composition of a problematic tissue reveals new insight including metakaryotic cells.

BACKGROUND: Calcifications of atherosclerotic plaques represent a controversial issue as they either lead to the stabilization or rupture of the lesion. However, the cellular key players involved in the progression of the calcified plaques have not yet been described. The primary reason for this lacuna is that decalcification procedures impair protein and nucleic acids contained in the calcified tissue. The aim of our study was to preserve the cellular content of heavily calcified plaques with a new rapid fixation in order to simplify the study of calcifications. METHODS: Here we applied a fixation method for fresh calcified tissue using the Carnoy's solution followed by an enzymatic tissue digestion with type II collagenase. Immunohistochemistry was performed to verify the preservation of nuclear and cytoplasmic antigens. DNA content and RNA preservation was evaluated respectively with Feulgen staining and RT-PCR. A checklist of steps for successful image analysis was provided. To present the basic features of the F-DNA analysis we used descriptive statistics, skewness and kurtosis. Differences in DNA content were analysed with Kruskal-Wallis and Dunn's post tests. The value of P < 0.05 was considered significant. RESULTS: Twenty-four vascular adult tissues, sorted as calcified (14) or uncalcified (10), were processed and 17 fetal tissues were used as controls (9 soft and 8 hard). Cells composing the calcified carotid plaques were positive to Desmin, Vimentin, Osteocalcin or Ki-67; the cellular population included smooth muscle cells, osteoblasts and osteoclasts-like cells and metakaryotic cells. The DNA content of each cell type found in the calcified carotid artery was successfully quantified in 7 selected samples. Notably the protocol revealed that DNA content in osteoblasts in fetal control tissues exhibits about half (3.0 ng) of the normal nuclear DNA content (6.0 ng). CONCLUSION: Together with standard histology, this technique could give additional information on the cellular content of calcified plaques and help clarify the calcification process during atherosclerosis.

CoCl2 Administration to Vascular MSC Cultures as an In Vitro Hypoxic System to Study Stem Cell Survival and Angiogenesis.

Mesenchymal stem cells (MSCs) possess well-known reparative properties, among which the ability to form neovessels; in vivo, this characteristic is carried out both in a normal and in a pathological setting. Hypoxia, a condition common to many human diseases, is known to promote angiogenesis and to improve stem cell proliferation and differentiation. For this purpose, we provide an experimental protocol to test stem cell viability and angiogenesis under hypoxic conditions, comparing a vascular model of MSCs with stable cell lines. In order to avoid the use of expensive facilities, we propose the application of a chemical hypoxia inducer, cobalt chloride.

The incidence and morphology of Monckeberg's medial calcification in banked vascular segments from a monocentric donor population.

Little is known about the real incidence and the clinical relevance of the enigmatic Monckeberg's medial calcification in the patency of the femoral artery allograft. Here we present a retrospective study on 143 multiorgan donors (mean age 38 years, range 14-59 years), to describe the incidence and the morphological features of vascular calcifications in banked femoral arteries suitable for clinical use. In the present series, focal vascular calcifications were present in 36 (25 %) cases, 23 cases localized in the intima, 7 in the media, and 6 were mixed. No correlation was found between the incidence of calcifications and the classical cardiovascular clinical risk factors (n = 9); only hypertension correlated with the medial localization, but not with the incidence, of the calcification (P = 0.017). While the macroscopic exclusion criteria of vascular grafts include atheromatous and not-atheromatous lesions, we ignore the actual impact of Monckeberg's medial calcification on vessel transplantation and allograft life. In our opinion this is a very important topic, since when the histological criteria for Monckeberg's calcification diagnosis are used, 25 % of our young donors population was affected. Whether Monckeberg's medial calcification is a stable arterial condition, apparently underestimated in the general population, or a dynamic process evolving with age and atherosclerosis, or a banking-related vascular alteration, still remain an open issue deserving further studies with subjects of different ages.

Facing the enigma of the vascular network in hepatocellular carcinomas in cirrhotic and non-cirrhotic livers.

AIMS: In this paper we aimed to analyse the typology and the phenotype of the different vascular modifications in human hepatocellular carcinomas (HCCs) with a new immunomorphological and gene expression approach. We also attempted to correlate these modifications with the histological parameters of tumour aggressiveness and the surrounding liver parenchyma. METHODS: Ninety-six HCCs (from 80 patients) were retrospectively enrolled, 46 occurring in non-cirrhotic livers, and 50 in livers transplanted for cirrhosis. Histopathological analysis, immunohistochemistry for CD34, Nestin and WT1 and RT-PCR for Nestin, transforming growth factor-ß1 (TGFß1) and insulin-like growth factor 1 (IGF1R) mRNA were performed in all nodules. RESULTS: By correlating the CD34 and Nestin immunoreactivity in HCC vasculature with the tumorous architecture, we identified four vascular patterns (named from 'a' to 'd'). Each of them was characterised by different expressions of TGFß1 and IGF1R mRNA. Pattern a showed CD34-positive/Nestin-negative sinusoids, and was prevalent in microtrabecular lesions. Pattern b showed similar morphology and architecture as pattern a, but with Nestin-positive sinusoids and a significant 'boost' in IGF1R and TGFß1 mRNAs. In patterns c and d a progressive sinusoid loss and a gain of newly formed arterioles were seen. Notably, HCCs with pattern a arose more frequently in cirrhosis (p=0.024), and showed lower incidence of microvascular invasion (p=0.002) and infiltration (p=0.005) compared with HCCs with other patterns. CONCLUSIONS: Although future studies are surely required, the identification of different vascular profiles in HCCs from cirrhotic and non-cirrhotic livers may help clarify the relationship between HCC progression and aggressiveness.

High sensitivity C-reactive protein and vascular endothelial growth factor as indicators of carotid plaque vulnerability.

BACKGROUND: Carotid atherosclerotic plaques are one of the causes of cerebral stroke. The risk is higher for the vulnerable plaques but there are no specific markers to identify them. The aim of our study was to identify vulnerable carotid plaques by the mean of atherosclerotic serological markers in patients undergoing carotid revascularization by endarterectomy (CEA) or stenting (CAS). METHODS: High sensitivity C-reactive protein (hsCRP) and vascular-endothelial-growth-factor (VEGF) levels were assessed preoperatively in patients undergoing carotid revascularization. Carotid plaques vulnerability were investigated in two different methods: the "biological vulnerability" with the histological evaluation of the plaques from CEA, scoring five parameters (microvessel density, fibrous-cap-thickness, calcification, inflammatory infiltrate and lipid core), and the "structural vulnerability" with the evaluation of the plaques debris detached during CAS and captured by the cerebral protection filter, in terms of percentage of filter pores occlusion (OP). Results were correlated using χ2, Fisher's, Mann-Whitney, Student's t-tests and regression analysis. RESULTS: The histological analysis was performed in 40 specimens, vulnerable plaques (30%) were correlated with higher hsCRP levels (>5mg/l; OR, 2.5; CI 95%, 1.1-5.5; P=0.01) and VEGF levels (VEGF>500 pg/l; OR 3.0, CI 95%, 1.1-7.7; P=0.01). All the filters (N.40) contained microscopic debris (mean OP 26.6%±9.9); higher hsCRP levels (>5mg/l) were correlated with greater than 25% OP (OR, 2.6; CI 95%, 1.2-5.7). An increase in the percentage of OP was also observed in patients with VEGF>500 pg/l (OR, 2.9; CI, 95% 1.3-6.3). CONCLUSIONS: This study suggests that serological determinants are useful in recognizing the structural and biological vulnerability of carotid plaques.

In vitro alteration of physiological parameters do not hamper the growth of human multipotent vascular wall-mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSCs) with multilineage potential and anti-inflammatory property can be isolated from different human tissues, representing promising candidates in regenerative medicine. Despite the common criteria of characterization, many factors contribute to MSC heterogeneity (i.e., tissue origin, coexistence of cell subsets at different stage of differentiation, epigenetic) and no standard methods have been approved to characterize MSCs in cell culture. AIM: The present study aimed to test whether MSCs resist adverse chemical and physical culture conditions, surviving MSC subpopulations are endowed with the stemness abilities; to characterize MMP expression in AAA-MSCs under the adverse experimental conditions. METHODS AND RESULTS: MSCs enzymatically isolated from human abdominal aortic aneurysm (AAA-MSCs) were exposed to media acidification, hypoxia, starving, drying and hypothermia through the following strategies: (1) low-density seeding in closed flasks; (2) exposure to a chemical hypoxia inducer, cobalt chloride; (3) exposure to a dry environment with growing medium deprivation and culture at 4°C. None of these conditions affected MSC viability and stemness profile, as evidenced by NANOG, OCT-4, and SOX-2 mRNA expression in surviving cells. A significant MMP-9 decrease, especially when AAA-MSCs were exposed to hypothermia, was associated with stress resistant stem cells. CONCLUSIONS: AAA-MSCs survive to extremely adverse culture conditions, keeping their morphology and stemness features. Besides MMP-9 role in pathological tissue remodeling, this protease may be related to MSC survival. Future studies on MSCs derived from other tissues will be necessary to refine our culture protocol, which can represent an empirical method to demonstrate MSC stemness, with potential implications for their clinical use.

Diffuse calcifications protect carotid plaques regardless of the amount of neoangiogenesis and related histological complications.

BACKGROUND: Neoangiogenesis is crucial in plaque progression and instability. Previous data from our group showed that Nestin-positive intraplaque neovessels correlated with histological complications. The aim of the present work is to evaluate the relationship between neoangiogenesis, plaque morphology, and clinical instability of the plaque. MATERIALS AND METHODS: Seventy-three patients (53 males and 20 females, mean age 71 years) were consecutively enrolled. Clinical data and 14 histological variables, including intraplaque hemorrhage and calcifications, were collected. Immunohistochemistry for CD34 and Nestin was performed. RT-PCR was performed to evaluate Nestin mRNA (including 5 healthy arteries as controls). RESULTS: Diffusely calcified plaques (13/73) were found predominantly in females (P = 0.017), with a significantly lower incidence of symptoms (TIA/stroke (P = 0.019) than noncalcified plaques but with the same incidence of histological complications (P = 0.156)). Accordingly, calcified and noncalcified plaques showed similar mean densities of positivity for CD34 and Nestin. Nestin density, but not CD34, correlated with the occurrence of intraplaque hemorrhage. CONCLUSIONS: Plaques with massive calcifications show the same incidence of histological complications but without influencing symptomatology, especially in female patients, and regardless of the amount of neoangiogenesis. These results can be applied in a future presurgical identification of patients at major risk of developing symptoms.

Arterial calcification: Finger-pointing at resident and circulating stem cells.

The term ''Stammzelle'' (stem cells) originally appeared in 1868 in the works of Ernst Haeckel who used it to describe the ancestor unicellular organism from which he presumed all multicellular organisms evolved. Since then stem cells have been studied in a wide spectrum of normal and pathological conditions; it is remarkable to note that ectopic arterial calcification was considered a passive deposit of calcium since its original discovering in 1877; in the last decades, resident and circulating stem cells were imaged to drive arterial calcification through chondro-osteogenic differentiation thus opening the idea that an active mechanism could be at the basis of the process that clinically shows a Janus effect: calcifications either lead to the stabilization or rupture of the atherosclerotic plaques. A review of the literature underlines that 130 years after stem cell discovery, antigenic markers of stem cells are still debated and the identification of the osteoprogenitor phenotype is even more elusive due to tissue degradation occurring at processing and manipulation. It is necessary to find a consensus to perform comparable studies that implies phenotypic recognition of stem cells antigens. A hypothesis is based on the singular morphology and amitotic mechanism of division of osteoclasts: it constitutes the opening to a new approach on osteoprogenitors markers and recognition. Our aim was to highlight all the present evidences of the active calcification process, summarize the different cellular types involved, and discuss a novel approach to discover osteoprogenitor phenotypes in arterial wall.

Nestin and WT1 expression in atheromathous plaque neovessels: association with vulnerability.

INTRODUCTION: Neoangiogenesis is crucial for the progression and vulnerability of atheromasic lesions. Since adult vasa vasorum, which represent the neoangiogenetic burden of healthy arteries, constitutively express Nestin and Wilms Tumor (WT1), the aims of the present study are: i) to describe and quantify Nestin and WT1 in plaque neovessels; ii) to investigate the relationship between neovessel phenotype and plaque instability. METHODS: We prospectively evaluated 49 consecutive carotid endarterectomy specimens. Histopathological characteristics were separately collected, particularly the intraplaque histological complications. Immunohistochemistry was carried out for CD34, Nestin and WT1; the density of positivity was evaluated for each marker. RT-PCR was performed to assess Nestin and WT1 mRNA levels on the first 10 plaques and on 10 control arteries. RESULTS: Six (12.2%) plaques showed no neoangiogenesis. In the others, the mean immunohistochemical densities of CD34, Nestin, and WT1-positive structures were 41.88, 28.84 and 17.68/mm2. Among the CD34+ neovessels, 68% and 42% expressed Nestin and WT1 respectively, i.e., nearly 36% of the neovessels resulted to be Nestin+/WT1-. Furthermore, complicated plaques (n=30) showed significantly more CD34 and Nestin-positive vessels than uncomplicated plaques (n=13; P=0.045 and P=0.009), while WT1 was not increased (P=0.139). RT-PCR confirmed that WT1 gene expression was 3-fold lower than Nestin gene in plaques (p=0.001). CONCLUSIONS: Plaque neoangiogenesis shows both a Nestin+/WT1- and a Nestin+/WT1+ phenotype. The Nestin+/WT1- neovessels are significantly more abundant in complicated (vulnerable) plaques. The identification of new transcription factors in plaque neoangiogenesis, and their possible regulation, can open new perspectives in the therapy of vulnerable plaques.