Vrednotenje perfuzije mišjih in pasjih tumorjev ter prašičjih jeter po elektroporaciji s slikovno-diagnostičnimi metodami

Brložnik, Maja (author), Pavlin, Darja (mentor), Kranjc, Simona (co-mentor)

Namen doktorske disertacije je bil ovrednotenje rezultatov slikovno-diagnostičnih metod po elektroporaciji (EP) in elektrokemoterapiji (EKT) jeter zdravih prašičev za preučitev varnostnega vidika EKT globoko ležečih jetrnih tumorjev ter rezultatov ultrazvočnega pregleda s kontrastnim sredstvom (UZ KS) po EKT in genskem elektroprenosu (GEP) mišjih in pasjih tumorjev kot prediktivnih dejavnikov zdravljenja. Slikovno-diagnostične spremembe po EP in EKT z bleomicinom (BLM) v jetrnem parenhimu in velikih krvnih žilah jeter zdravega prašiča s potencialno nevarno vstavitvijo linearnih in heksagonalnih elektrod v velike jetrne žile smo preučili z ultrazvočno preiskavo takoj po EP/EKT ter z računalniško tomografijo od 60 do 90 minut in en teden po EP/EKT. Rezultati slikovno-diagnostičnih metod jeter prašičev po EK so pokazali zmanjšano perfuzijo tretiranega področja. Spremembe niso bile posledica uporabe BLM, saj so bile enake pri poskusni in kontrolni skupini, kjer smo aplicirali samo električne pulze. Namerna vstavitev elektrod in aplikacija električnih pulzov neposredno v svetlino velikih žil ni povzročila tromboz, krvavitev ali drugih hemodinamskih motenj. Kot model preiskovanja uporabnosti UZ-KS kot prediktivnega dejavnika zdravljenja s terapevtskimi metodami, ki temeljijo na EP, smo uporabili miši z induciranimi melanomi. V prvi raziskavi smo na mišjem modelu, ki smo ga zdravili z obsevanjem in GEP plazmidne DNA, ki utiša adhezijsko molekulo celic melanoma, opazili značilno zmanjšanje perfuzije tumorjev v terapevtskih skupinah v primerjavi s kontrolnimi skupinami, rezultati UZ-KS pa so korelirali z zmanjšano gostoto žil. Povprečne vrednosti parametra, ki opisuje volumen pretoka, so bile značilno nižje pri tumorjih, ki so se odzvali na terapijo s popolnim odgovorom, in vrednosti PE so pokazale trend korelacije s protitumorsko učinkovitostjo. V drugi raziskavi na mišjih melanomih, zdravljenih z EKT z BLM v kombinaciji z GEP plazmida za interlevkin 12 (pIL-12), je UZ-KS pokazal zmanjšano perfuzijo v skupinah z daljšim časom podvojitve volumna tumorja in prediktivno vrednost UZ KS smo potrdili s statistično značilnimi Pearsonovimi koeficienti. S krajšim časom podvojitve volumna tumorja je bila povezana tudi večja heterogenost perfuzije tumorja. V klinični del raziskave smo vključili pse s kožnimi in podkožnimi tumorji, ki so bili zdravljeni s standardnim postopkom kombinacije EKT in GEP pIL-12. Rezultate UZ-KS smo primerjali z izidom zdravljenja. Tudi v klinični raziskavi pri psih smo ugotovili številne razlike v parametrih UZ KS med tumorji s popolnim odgovorom in tumorji z nepopolnim odgovorom: perfuzija in heterogenost perfuzije sta bili manjši pri tumorjih s popolnim odgovorom.

• Language: Slovenian
• Keywords: kožne novotvorbe, jetra, elektrokemoterapija, bleomicin, elektroporacija, tehnike genskega prenosa, plazmidi, interlevkin-12, ultrasonografija, kontrastna sredstva, računalniška tomografija, izid zdravljenja, živalski modeli, miši, psi, prašiči
• Work type: Doctoral dissertation
• Organization: VF - Veterinary Faculty
• Year: 2021
• PID: 20.500.12556/RUL-132919
• Publication date in RUL: 06.11.2021

Secondary language

• Language: English
• Title: Perfusion assessment of murine and canine tumors and porcine liver after electroporation with diagnostic imaging methods

Abstract

The aim of this dissertation was to evaluate the results of diagnostic imaging after electroporation (EP) and electrochemotherapy (ECT) of porcine liver to investigate the safety aspect of ECT of deep-seated liver tumors and the results of dynamic contrast-enhanced ultrasound (DCE US) after ECT and gene electrotransfer (GET) of murine and canine tumors as potential predictive factors in treatment. Radiological findings after EP and ECT with bleomycin (BLM) on the hepatic parenchyma and major blood vessels of the liver of a healthy pig with potentially dangerous insertion of the electrodes into the major hepatic vessels were examined by ultrasound immediately after ECT and by computed tomography from 60 to 90 minutes and one week after ECT with linear and hexagonal electrodes. The results of diagnostic imaging of the porcine liver after ECT showed decreased blood flow in the treated area. The changes were not due to the use of BLM, as they were the same in the experimental and control groups, where only electrical pulses were administered. Intentional insertion of electrodes and application of electrical pulses directly into the lumen of large vessels did not result in thrombosis, haemorrhage, or other hemodynamically significant injury. Mice with induced melanoma were used as a model to investigate the utility of DCE-US as a prognostic factor for treatment with EP-based therapies. In the first study in a mouse model treated with irradiation and GET of plasmid DNA that silences the melanoma cell adhesion molecule, we observed a decrease in tumor perfusion in the treatment groups compared with the control groups, and the results of DCE US correlated with decreased vessel density detected histologically. Furthermore, mean values of parameters describing flow volume were significantly lower in tumors with complete response, and they showed a trend toward correlation with antitumor efficacy. In the second study, mouse melanomas were treated with ECT in combination with GET of plasmid DNA encoding interleukin-12 (pIL-12). DCE US showed reduced perfusion in groups with longer tumor volume doubling time, and the predicted DCE US value was confirmed by statistically significant Pearson coefficients. In addition, greater tumor perfusion heterogeneity was associated with shorter tumor doubling time. The clinical study included dogs with cutaneous and subcutaneous neoplasms treated with a standard procedure combining ECT and GET pIL-12. We also found a number of differences in DCE-US parameters between tumors with complete response and tumors with incomplete response in the clinical study: Perfusion and perfusion heterogeneity were lower in tumors with complete response.

• Keywords: skin neoplasms, liver, electrochemotherapy, bleomycin, electroporation, gene transfer techniques, plasmids, interleukin-12, ultrasonography, contrast media, tomography x-ray computed, treatment outcome, models animal, mice, dogs, swine