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BACKGROUND The persisting organ shortage in the field of transplantation recommends the use of marginal kidneys which poorly tolerate ischemic damage. Adenosine triphosphate (ATP) depletion during cold ischemia time (CIT) is considered crucial for graft function. We tested different strategies of kidney perfusion before transplantation in the attempt to improve the technique. MATERIAL AND METHODS Twenty human discarded kidneys from donors after brain death and with at least 20 hours of CIT were randomized to the following experimental groups (treatment time three-hours at 4°C): a) static cold storage (CS); b) static cold hyperbaric oxygenation (Hyp); c) hypothermic perfusion (PE); d) hypothermic perfusion in hyperbaric oxygenation (PE-Hyp); and e) hypothermic oxygenated perfusion (PE-O2). RESULTS Histological results showed that perfusion with or without oxygen did not produce any endothelial damage. A depletion of ATP content following the preservation procedure was observed in CS, PE, and Hyp, while PE-Hyp and PE-O2 were associated with a net increase of ATP content with respect to baseline level. In addition, PE-Hyp was associated with a significant downregulation of endothelial isoform of nitric oxide synthase (eNOS) gene expression and of hypoxia inducible factor-1α (HIF-1α). CONCLUSIONS Hyperbaric or normobaric oxygenation with perfusion improves organ metabolic preservation compared to other methods. This approach may prevent the onset of delayed graft function, but clinical trials are needed to confirm this.

Obeticholic acid (OCA) is a semisynthetic bile acid (BA) analog and potent farnesoid X receptor agonist approved to treat cholestasis. We evaluated the biodistribution and metabolism of OCA administered to carbon tetrachloride-induced cirrhotic rats. This was to ascertain if plasma and hepatic concentrations of OCA are potentially more harmful than those of endogenous BAs. After administration of OCA (30 mg/kg), we used liquid chromatography–mass spectrometry to measure OCA, its metabolites, and BAs at different timepoints in various organs and fluids. Plasma and hepatic concentrations of OCA and BAs were higher in cirrhotic rats than in controls. OCA and endogenous BAs had similar metabolic pathways in cirrhotic rats, although OCA hepatic and intestinal clearance were lower than in controls. BAs' qualitative and quantitative compositions were not modified by a single administration of OCA. In all the matrices studied, OCA concentrations were significantly lower than those of endogenous BAs, potentially much more cytotoxic.

Introduction. Intimal hyperplasia (IH) is characterized by concentric lumen constriction due to marked vascular cell proliferation and is associated with arteriovenous fistula (AVF) early failure in haemodialysis patients. Aim. The present study aimed at establishing ex-vivo cell cultures from patients enrolled for AVF procedure, in order to identify the main cellular and molecular mediators of IH. Methods. Tissues and cells were collected from i) normal veins taken when the first AVF was established, and ii) AVF with IH. Formalin-fixed paraffin-embedded tissue sections were stained with anti CD34, CD44 and MMP-9 monoclonal antibodies. Isolated vascular cells were investigated for bromo-deoxy-uridine incorporation, and migration ability; immunofluorescence (CD34, CD44, ASMA, SOX9) was used to characterize the cell phenotype. Results. Tissue detection of CD34+, CD44+ cells within the IH lesions suggested the involvement of endothelial cells in AVF failure. The expression of MMP-9 protein in the same area supported the activation of migration/matrix remodeling pathways, typical of mesenchymal cells. This same immunophenotype was observed in the cells harvested from IH lesions, together with the detection of ASMA. We observed significant growth differences between cells isolated from normal veins and AVF with IH. Indeed, cells from IH grew faster than cells from normal veins; moreover, IH cells expressed higher levels of SOX9, a transcription factor associated with cell proliferation, and exhibited a marked migration property. Conclusion. Our data evidence that, when compared with cells harvested from not diseased veins, cells derived from AVF with IH have increased proliferation, migration and remodeling abilities. The immunophenotype documented in tissue and cell studies suggests that the endothelial-mesenchymal transition is involved in IH formation and progression. This preliminary study will be expanded with further investigations on IH induction mechanisms and on possible therapeutic targets.

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Introduction. Vasa vasorum (VV) neovasculogenic potential is now widely accepted, and possibly related to the presence of progenitor cells. We studied the morphology of VV in healthy arteries and their immunohistochemical (IHC) expression of Nestin and WT1, two markers of endothelial progenitor cells. Materials and Methods. Twenty arteries from 16 multiorgan donors were analyzed; IHC was performed manually (CD34, CD31, Nestin) or automatically (WT1). Microvessel positivity “density” for each antibody was calculated dividing vascular adventitia in 1-mm2 fields with an ocular micrometer. Double immunofluorescence was used to investigate Nestin and WT1 co-localization in VV. Results. The mean positivity “densities” for CD31, CD34, Nestin and WT1 were 13.63, 12.20, 8.90 and 7.98/mm2 respectively. Mean Nestin/CD31 and WT1/CD31 ratios were 0.69 and 0.63 respectively. VV

Histological quality assessment of donated livers is a key factor for extending the cadaveric donor pool for liver transplantation. We retrospectively compared frozen-section analysis with routine histological permanent slides and the outcomes of grafts in liver biopsies from 294 candidate donors. The kappa concordance coefficient of agreement between frozen-section analysis and routine histological analysis was very good for macrosteatosis (kappa = 0.934), microsteatosis (kappa = 0.828), and total steatosis (kappa = 0.814). The correlation between the mean amounts of macrosteatosis, microsteatosis, and total steatosis in frozen and permanent sections was also significant (P < 0.001, Spearman's test). Macrosteatosis and microsteatosis were overestimated to >30% in 4 of 32 cases (12.5%) and in 23 of 62 cases (37.1%), respectively. The only 2 histological parameters of frozen sections able to predict graft dysfunction within 7 days of transplantation were macrosteatosis and total steatosis (P = 0.018 and P = 0.015, respectively, Mann-Whitney test). None of the other histopathological features evaluated in frozen sections, including portal inflammation, lobular necrosis, myointimal thickening, biliocyte regression, cholestasis, hepatocellular polymorphism, lipofuscin storage, and fibrous septa, were significantly correlated with the graft outcome. The frozen-section histological evaluation of biopsies from cadaveric liver donors is an accurate, time-effective, and predictive method for the assessment of graft suitability.

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.

The molecular background of hepatocellular carcinoma (HCC) is highly heterogeneous, and biomarkers predicting response to treatments are an unmet clinical need. We investigated miR-30e-3p contribution to HCC phenotype and response to sorafenib, as well as the mutual modulation of TP53/MDM2 pathway, in HCC tissues and preclinical models. MiR-30e-3p was downregulated in human and rat HCCs, and its downregulation associated with TP53 mutations. TP53 contributed to miR-30e-3p biogenesis, and MDM2 was identified among its target genes, establishing an miR-30e-3p/TP53/MDM2 feedforward loop and accounting for miR-30e-3p dual role based on TP53 status. EpCAM, PTEN, and p27 were demonstrated as miR-30e-3p additional targets mediating its contribution to stemness and malignant features. In a preliminary cohort of patients with HCC treated with sorafenib, increased miR-30e-3p circulating levels predicted the development of resistance. In conclusion, molecular background dictates miR-30e-3p dual behavior in HCC. Mdm2 targeting plays a predominant tumor suppressor function in wild-type TP53 contexts, whereas other targets such as PTEN, p27, and EpCAM gain relevance and mediate miR-30e-3p oncogenic role in nonfunctional TP53 backgrounds. Increased circulating levels of miR-30e-3p predict the development of sorafenib resistance in a preliminary series of patients with HCC and deserve future investigations. Significance: The dual role of miR-30e-3p in HCC clarifies how the molecular context dictates the tumor suppressor or oncogenic function played by miRNAs.

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.

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.