Molecular imaging of gene transduction in cardiac transplantation

This thesis is based on a series of experiments aimed at designing a model of gene transfer to the transplanted heart. The use of viral vector-based gene therapy to target pathological processes following cardiac transplantation faces many challenges including the potential effects of the virus on the host as well as the need to establish the presence of the gene in the target organ. In the first set ofexperiments (Chapter 2), concerns over the effects of adenoviral gene transfer on the later development of cardiac allograft vasculopathy (CAV) were addressed. Heterotopically transplanted cardiac allografts from Brown Norway to Lewis rats revealed the presence of CAV at 120 days. Ex vivo adenoviral serotype 5 perfusion of the donor heart did not affect the later development of allograftvasculopathy.In the second series of experiments, the feasibility of visualizing the presence of the sodium iodide symporter (hNIS) non-invasively following its gene transduction was established with the use of SPECT imaging. Following gene transfer, the recipients were injected with ⁹⁹mTc in the first set of experiments (Chapter 3) or with radioactive ¹²³I (Chapter 4) and imaged under a SPECT scanner. Radioactive isotope uptake in the Ad-NIS group was significantly higher than in the group of animals whose hearts were perfused with just University of Wisconsin solution or with blank adenovirus without a marker gene. Sequential imaging of Ad-NIS-perfused hearts between post-operative days 2 and 14 revealed peak image intensity at day 5. Overall, image intensities correlated with ex vivo counts of radioactivity.These data demonstrate that hNIS is an excellent reporter gene whose expression can be accurately and non-invasively monitored by serial radioisotope single photon emission computed tomography (SPECT) imaging

ENDOCRINE TUMOURS: Imaging in the follow up of differentiated thyroid cancer: current evidence and future perspectives for a risk-adapted approach

The clinical and epidemiological profiles of differentiated thyroid cancers (DTCs) have changed in the last three decades. Today's DTCs are more likely to be small, localized, asymptomatic papillary forms. Current practice is though moving towards more conservative approaches (e.g. lobectomy instead of total thyroidectomy, selective use of radioiodine). This evolution has been paralleled and partly driven by rapid technological advances in the field of diagnostic imaging. The challenge of contemporary DTCs follow up is to tailor a risk-of-recurrence-based management, taking into account the dynamic nature of these risks, which evolve over time, spontaneously and in response to treatments. This review provides a closer look at the evolving evidence-based views on the use and utility of imaging technology in the post-treatment staging and the short- and long-term surveillance of patients with DTCs. The studies considered range from cervical US with Doppler flow analysis to an expanding palette of increasingly sophisticated second-line studies (cross-sectional, functional, combined-modality approaches), which can be used to detect disease that has spread beyond the neck and, in some cases, shed light on its probable outcome. 

12 Chapters on Nuclear Medicine

The development of nuclear medicine as a medical specialty has resulted in the large-scale application of its effective imaging methods in everyday practice as a primary method of diagnosis. The introduction of positron-emitting tracers (PET) has represented another fundamental leap forward in the ability of nuclear medicine to exert a profound impact on patient management, while the ability to produce radioisotopes of different elements initiated a variety of tracer studies in biology and medicine, facilitating enhanced interactions of nuclear medicine specialists and specialists in other disciplines. At present, nuclear medicine is an essential part of diagnosis of many diseases, particularly in cardiologic, nephrologic and oncologic applications and it is well-established in its therapeutic approaches, notably in the treatment of thyroid cancers. Data from official sources of different countries confirm that more than 10-15 percent of expenditures on clinical imaging studies are spent on nuclear medicine procedures

MUC1 positive, Kras and Pten driven mouse gynecologic tumors replicate human tumors and vary in survival and nuclear grade based on anatomical location

Activating mutations of Kras oncogene and deletions of Pten tumor suppressor gene play important roles in cancers of the female genital tract. We developed here new preclinical models for gynecologic cancers, using conditional (Cre-loxP) mice with floxed genetic alterations in Kras and Pten. The triple transgenic mice, briefly called MUC1KrasPten, express human MUC1 antigen as self and carry a silent oncogenic KrasG12D and Pten deletion mutation. Injection of Cre-encoding adenovirus (AdCre) in the ovarian bursa, oviduct or uterus activates the floxed mutations and initiates ovarian, oviductal, and endometrial cancer, respectively. Anatomical site-specific Cre-loxP recombination throughout the genital tract of MUC1KrasPten mice leads to MUC1 positive genital tract tumors, and the development of these tumors is influenced by the anatomical environment. Endometrioid histology was consistently displayed in all tumors of the murine genital tract (ovaries, oviducts, and uterus). Tumors showed increased expression of MUC1 glycoprotein and triggered de novo antibodies in tumor bearing hosts, mimicking the immunobiology seen in patients. In contrast to the ovarian and endometrial tumors, oviductal tumors showed higher nuclear grade. Survival for oviduct tumors was significantly lower than for endometrial tumors (p = 0.0015), yet similar to survival for ovarian cancer. Oviducts seem to favor the development of high grade tumors, providing preclinical evidence in support of the postulated role of fallopian tubes as the originating site for high grade human ovarian tumors. © 2014 Tirodkar et al

PSMA PET-guided protective strategies against radiation therapy induced salivary gland toxicity

This thesis explores the innovative application of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging, traditionally used for prostate cancer staging, to assess salivary gland toxicity from radiation therapy and develop strategies to mitigate it. Radiotherapy, a cornerstone in cancer treatment, often results in unavoidable exposure of healthy tissues to radiation, leading to toxicity. The salivary glands are highly sensitive to radiation and can suffer damage, manifesting as xerostomia or dry mouth, significantly affecting patients' quality of life. Traditional methods for evaluating salivary gland damage are unreliable, necessitating more precise evaluation techniques. The thesis presents a case series highlighting the variability in PSMA uptake patterns in patients treated with 131I therapy for thyroid cancer, underscoring the modality's ability to reveal functional variations undetectable by traditional methods. Further, it investigates potential protective strategies against salivary gland toxicity in radionuclide therapy, notably evaluating the effects of glycopyrronium bromide (GPB) and gustatory stimulation on PSMA uptake. Interestingly, GPB did not reduce PSMA-ligand or 131I uptake, while eating or gustatory stimulation was advised against during therapy due to its potential to exacerbate PSMA uptake.The research also outlines the derivation of dose-response curves for salivary glands from external beam radiotherapy using PSMA PET, and suggests an optimization path for reducing toxicity further. This thesis signifies a significant step forward in utilizing functional imaging for toxicity evaluation and treatment optimization in cancer therapy, opening avenues for its application in other normal tissues

Implant-prosthetic therapy failure in smoker and nonsmoker patients

Introduction: Implant-prosthetic therapy has predictable success, and the complications are associated with a lot of factors. Smoking cigarettes is reason for different oral diseases, bone loss, loss of soft tissue and teeth, appearance of periimplantitis and implant loss. The corellation of smoking and implant-prosthetic therapy failure was examined in the clinical study. Materials and method: Fifty patients with FDP on 61 implants in frontal and molar region were investigated. They were divided in two groups: smokers and nonsmokers. Thirty four patients were smokers, and sixteen didn’t smoke cigarettes in the last two years. Criteria data for the success of the therapy were mobility of the implant, pain, peri-implant bone loss higher than 1.5 mm, absence of technical complications and function and aesthetics appeal. Control checkups were made after six months, one and two years. Patients had questionnaires, clinical examination and X-ray. Results: There is a statistically significant difference between smokers and nonsmokers in the failure rates of dental implants. During first year 0,5 mm of bone was lost around eleven implants, and 0,05 mm next years.Total seven implants failed, five in smoker group at the beginning of the first year, and 2 in nonsmoker group during second year. Conclusion: Results showed that smoking habit can increase the risk of early implants loss two times more often in smokers. For some complications like periimplantitis, local factors have greater influence. Smoking does not increase the risk of late implant loss, but the implants at patients with smoking habit, in correlation with several different local risk factors, is contraindicated. Early complications are results of smoking, while quality and quantity of surrounding bone are responsible for late complications.The results from the investigation, also give informations for proper treatment planning, and patient education for quiting their harmfull habit. Keywords Implants, therapy failure, smoking, periimplantitis

Characterization of a Novel Long Non-coding RNA Involved in Thyroid Differentiation

Thyroid is the endocrine gland that most frequently undergoes to congenital disorders or neoplastic transformation and despite its organogenesis is well characterized, molecular bases of early thyroid differentiation are still obscure. During last years, long non-coding RNAs (lncRNA) have acquired increasing relevance in many biological processes, such as differentiation and cancer. In E10.5 mouse thyroid bud the most enriched transcript resulted to be a poorly characterized lncRNA, that we named Thybe1 (thyroid bud enriched 1). Thybe1 is an antisense transcript of the protein-coding gene klhl14, also enriched in thyroid bud, to which it partially overlaps in a head-to-head arrangement. To shed light on its role, in this work we characterize such novel lncRNA, investigating its role in thyroid differentiation and its possible mechanism of action. Interestingly, our data reveal that Thybe1 is required for thyroid differentiation, in vitro, and is able to compete, for miR182a-5p binding, with Pax8 and Bcl2, both playing a key role in thyroid survival and differentiation. Moreover, we observed that Thybe1 is dramatically repressed during thyroid carcinogenesis, being inversely correlated with miR182a-5p expression, both in vitro and in vivo. Furthermore, we noted that Thybe1 expression positively correlates with that of Klhl14 in several cell types, suggesting that this lncRNA is also able to act in cis on this target. In conclusion we describe for the first time a lncRNA involved in thyroid differentiation and carcinogenesis, and start to highlight its ability to act as a competing endogenous RNA for key developmental genes, thus identifying a novel candidate gene playing a role in thyroid development defects and cancer

Advances in functional imaging of differentiated thyroid cancer

Abstract: The present review provides a description of recent advances in the field of functional imaging that takes advantage of the functional characteristics of thyroid neoplastic cells (such as radioiodine uptake and FDG uptake) and theragnostic approach of differentiated thyroid cancer (DTC). Physical and biological characteristics of available radiopharmaceuticals and their use with state-of-the-art technologies for diagnosis, treatment, and follow-up of DTC patients are depicted. Radioactive iodine is used mostly with a therapeutic intent, while PET/CT with 18F-FDG emerges as a useful tool in the diagnostic management and complements the use of radioactive iodine. Beyond 18F-FDG PET/CT, other tracers including 124I, 18F-TFB and 68Ga-PSMA, and new methods such as PET/MR, might offer new opportunities in selecting patients with DTC for specific imaging modalities or treatments