Impaired Flow-Mediated Dilation and Risk of Restenosis in Patients Undergoing Coronary Stent Implantation

Background— Impaired endothelial function is a key event in the atherosclerosis process and predicts future cardiovascular events in subjects with and without coronary artery disease (CAD). We performed the first prospective study evaluating whether early measurement of brachial artery endothelium-dependent dilation (flow-mediated dilation [FMD]) after coronary stenting could predict occurrence of in-stent-restenosis. Methods and Results— The study population included 136 patients with single-vessel CAD undergoing percutaneous coronary intervention (PCI) with stenting and at least 6 months of follow-up. All patients underwent ultrasound detection of brachial artery reactivity 30 days after PCI; FMD was investigated before and after 5 minutes of occlusion of the brachial artery, and nitroglycerin-mediated dilation was investigated before and after administration of sublingual nitrates. Clinical in-stent restenosis was demonstrated in 20 patients (15%), whereas 116 patients (85%) remained free of signs or symptoms of recurrent ischemia. FMD was significantly impaired in patients with restenosis versus those without restenosis (percent diameter variation 4.6±5.8% versus 9.5±6.6%, P =0.002); moreover, 4% of patients with FMD ≥7% (median value) developed in-stent restenosis versus 28% of those with FMD <7% ( P =0.0001). On multivariate analysis, FMD was the strongest predictor of restenosis (OR 4.5, 95% CI 2.4 to 12.0); conversely, nitroglycerin-mediated dilation did not independently predict the risk of restenosis (OR 2.4, 95% CI 0.8 to 6.3). Conclusions— This is the first prospective study indicating that impaired FMD independently predicts occurrence of in-stent restenosis in patients undergoing PCI. Early evaluation of endothelial function after stenting may represent a useful screening tool to stratify patients according to future risk of restenosis

Avatar di zebrafish allo scopo di testare la chemiosensibilita' di biopsie provenienti da pazienti affetti da tumori del pancreas

Negli ultimi decenni i dati di incidenza dei tumori del pancreas hanno mostrato un trend in aumento, con una sopravvivenza a 5 anni minore del 10%. Vi sono diversi tipi di tumori del pancreas, tra questi l’adenocarcinoma duttale pancreatico (PDAC) è la più comune neoplasia maligna, molto aggressiva e difficile da trattare. Sfortunatamente al momento della diagnosi clinica, l’80-90% dei pazienti presentano un tumore non resecabile. Nonostante i progressi ottenuti con la terapia mirata, si riscontra ancora l’assenza di metodi atti a predire la risposta paziente-specifica, e di conseguenza trattamenti su misura per il singolo paziente. Gli approcci “omics” sono usati per effettuare una stratificazione dei pazienti e per indirizzare la scelta della terapia con un approccio di medicina di precisione. Tuttavia questi metodi non considerano le dinamiche interazioni genetiche e non-genetiche che si innescano a seguito della terapia. A questo proposito sono emersi i modelli “avatar” in cui cellule tumorali primarie umane sono xenotrapiante in animali modello, al fine di testare, nella fase preclinica, i potenziali trattamenti farmacologici. Il mio lavoro di tesi si è inserito nell’ambito di uno studio osservazionale prospettico (NCT03668418) condotto presso l’Università di Pisa dal gruppo di ricerca della Prof.ssa Raffa, per validare l’uso di avatar di zebrafish come strumento predittivo del miglior schema terapeutico per pazienti affetti da tumori solidi. Nello specifico, sono stati reclutati 27 pazienti affetti da PDAC e sono stati effettuati xenotrapianti di frammenti di tessuto tumorale in embrioni di zebrafish a 48 ore dopo la fecondazione. Al fine di validare il modello avatar, è stata valutata la sopravvivenza a 48 ore dopo il trapianto e sono state eseguite analisi istologiche e immunoistochimiche per confermare la presenza del tessuto tumorale e l’attecchimento cellulare. Gli embrioni xenotrapiantati sono stati esposti alle diverse opzioni di chemioterapia comunemente somministrate nella pratica clinica (GEM, GEMOX, GEM/nab-P, FOLFOXIRI). La risposta tumorale ai differenti trattamenti chemioterapici è stata valutata secondo diversi parametri: l’analisi dell’area fluorescente relativa, l’analisi della variazione percentuale del volume secondo il modello lineare a effetti misti e l’applicazione dei criteri WHO. Al termine del lavoro di tesi, i risultati di sensibilità ai trattamenti chemioterapici ottenuti nella sperimentazione animale sono stati correlati con la risposta al trattamento chemioterapico somministrato in prima linea nella sperimentazione umana; dal confronto è emerso che gli avatar di zebrafish risultano essere predittivi in 12 casi su 16 di PDAC

Use of zebrafish embryos as avatar of patients with pancreatic cancer: A new xenotransplantation model towards personalized medicine

BACKGROUND The response to chemotherapy treatment of patients with pancreatic ductal adenocarcinoma (PDAC) is difficult to predict and the identification of patients who most likely will benefit from aggressive chemotherapy approaches is crucial. The concept of personalized medicine has emerged in the last years with the objective to tailor the medical treatment to the individual characteristics of each patient, and particularly to the tumor biology of each patient. The need for in-vivo xenotransplantation models for cancer patients has increased exponentially, and for this reason zebrafish avatars have gained popularity. Preliminary studies were conducted also with PDAC tissue. AIM To develop a simple, not expensive, diffusible zebrafish embryo model as avatar for patients affected by PDAC. METHODS Tumor tissue was taken from the surgical specimen by the histopathologist. After its fragmentation into small pieces, they are stained with CM-Dil. Small pieces of stained tissue were transplanted into the yolk of wt AB zebrafish embryos with a glass capillary needle. Embryos were incubated at 35 °C in E3 medium supplemented with 1% Pen/Strep in the presence or absence of drugs for the following days in respect of the treatment plan (Gemcitabine; Gemcitabine and Oxaliplatin; Gemcitabine and nab-Paclitaxel; 5-Fluorouracil and Folinic acid and Oxaliplatin and Irinotecan). The response of zebrafish xenografts to the chemotherapy options has been analyzed by monitoring the fluorescent stained area at 2 h post injection (hpi), 1 d and 2 d post injection (dpi). In each time point, the mean size of the stained area was measured by ImageJ and it was normalized with respect to the 1 dpi time point mean relative tumor area (RTA). We evaluated the effect of the chemotherapy exposition comparing the mean RTA of each treated subgroup and the control group and evaluating the percentage reduction of the mean RTA by comparing each treated subgroup with the control group. RESULTS Between July 2018 and October 2019, a total of 15 patients with pancreatic cancer were prospectively enrolled. In all cases, it was possible to take a fragment of the tumor from the surgical specimen for the xenotransplantation in the zebrafish embryos. The histological examination confirmed the presence of a PDAC in all cases. In absence of chemotherapy (control group), over time the Dil-stained area showed a statistically significant increase in all cases. A statistically significant reduction of the mean RTA in the treated subgroups for at least one chemotherapy scheme was reported in 6/15 (40%) cases. The analysis of the percentage reduction of the RTA in treated subgroups in comparison to the control group revealed the presence of a linear relationship in each subgroup between the percentage reduction of the RTA and the number of cases reporting each percentage threshold considered for the analysis. CONCLUSION Our model seems to be effective for the xenotransplantation of PDAC tissue and evaluation of the effect of each chemotherapy scheme on the xenotransplanted tumor tissue

The hemodynamic performance of balloon-expandable aortic bioprostheses in the elderly: a comparison between rapid deployment and transcatheter implantation

Surgical aortic valve replacement with a rapid deployment valve (RDV) is a relatively recent treatment option. The aim of this study was to compare the hemodynamic performance of balloon-expandable (BE)-RDVs and BE-transcatheter heart valves (THVs) in a high surgical risk and frail-elderly population