Bioconjugated ß-Cyclodextrin-Perfluorohexane Nanocone Clusters as Functional Nanoparticles for Nanoparticle-Mediated Histotripsy.

Nanocone clusters (NCCs) are new-generation agents of nanoparticle-mediated histotripsy (NMH) recently developed to address the limitations of previously designed nanodroplets (NDs). NCCs can be obtained by simply mixing FDA-approved cyclodextrins (CD) and suitable perfluorocarbons (PFCs), which result in smaller size aggregates, detectable PFC amount, and more stable long-term storage since the obtained powder can be stored and redispersed as needed. Previous experimental and computational studies showed that NCCs consist of an organization of inclusion complexes of CD and PFC around free PFC droplets, and their aggregate behavior depends on the localization of PFC in the cavity and the water solubility of CD derivatives. It has been shown that ß-cyclodextrin (ßCD) and perfluorohexane (PFH) are ideal candidates for NCCs that can be isolated as a powder with high PFC content among various CD and PFC derivatives. This study focuses on the further development of the selected NCC composition to enhance the potential of NMH therapy while also enabling more detailed future experiments in vitro and in vivo. It is aimed to show the bioconjugation potential of NCCs through the example of the most commonly used functionalization methods such as targeting, PEGylation, and fluorescent labeling. For this purpose, ßCD as a building block was monofunctionalized with groups such as azide, alkyne, and amine groups that allow for effective coupling reactions such as the "click" reaction and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling. These monofunctional ßCDs were used as building blocks of NCCs in the presence of PFH to obtain functional NCCs as precursors of bioconjugation. EPPT1 as a synthetic peptide specific to uMUC1 and folic acid (FA) as the most commonly used targeting agent along with PEGylation were successfully shown as bioconjugation examples. Lastly, fluorescently labeled NCCs were obtained via fluorescein isothiocyanate (FITC) and alkyne functional NCC reaction through propargyl amine and isothiocyanate group reaction. The obtained bioconjugates were tested in vitro to validate the conjugation, and the ability to lower the histotripsy cavitation threshold, which is necessary for NMH, was demonstrated for all bioconjugates. Overall, the results showed that all obtained bioconjugates successfully lowered the cavitation threshold pressure while also fulfilling the desired bioconjugation metrics to serve as improved tools to enhance NMH as a targeted noninvasive ablation method.

Rapid elimination of cervical cancer while maintaining the harms and benefits ratio of cervical cancer screening: a modelling study.

BACKGROUND: Human papillomavirus (HPV) vaccination and intensifying screening expedite cervical cancer (CC) elimination, yet also deteriorate the balance between harms and benefits of screening. We aimed to find screening strategies that eliminate CC rapidly but maintain an acceptable harms-benefits ratio of screening. METHODS: Two microsimulation models (STDSIM and MISCAN) were applied to simulate HPV transmission and CC screening for the Dutch female population between 2022 and 2100. We estimated the CC elimination year and harms-benefits ratios of screening for 228 unique scenarios varying in vaccination (coverage and vaccine type) and screening (coverage and number of lifetime invitations in vaccinated cohorts). The acceptable harms-benefits ratio was defined as the number of women needed to refer (NNR) to prevent one CC death under the current programme for unvaccinated cohorts (82.17). RESULTS: Under current vaccination conditions (bivalent vaccine, 55% coverage in girls, 27.5% coverage in boys), maintaining current screening conditions is projected to eliminate CC by 2042, but increases the present NNR with 41%. Reducing the number of lifetime screens from presently five to three and increasing screening coverage (61% to 70%) would prevent an increase in harms and only delay elimination by 1 year. Scaling vaccination coverage to 90% in boys and girls with the nonavalent vaccine is estimated to eliminate CC by 2040 under current screening conditions, but exceeds the acceptable NNR with 23%. Here, changing from five to two lifetime screens would keep the NNR acceptable without delaying CC elimination. CONCLUSIONS: De-intensifying CC screening in vaccinated cohorts leads to little or no delay in CC elimination while it substantially reduces the harms of screening. Therefore, de-intensifying CC screening in vaccinated cohorts should be considered to ensure acceptable harms-benefits ratios on the road to CC elimination.

Development of Acoustically Active Nanocones Using the Host-Guest Interaction as a New Histotripsy Agent.

Histotripsy is a noninvasive and nonthermal ultrasound ablation technique, which mechanically ablates the tissues using very short, focused, high-pressured ultrasound pulses to generate dense cavitating bubble cloud. Histotripsy requires large negative pressures (≥28 MPa) to generate cavitation in the target tissue, guided by real-time ultrasound imaging guidance. The high cavitation threshold and reliance on real-time image guidance are potential limitations of histotripsy, particularly for the treatment of multifocal or metastatic cancers. To address these potential limitations, we have recently developed nanoparticle-mediated histotripsy (NMH) where perfluorocarbon (PFC)-filled nanodroplets (NDs) with the size of ∼200 nm were used as cavitation nuclei for histotripsy, as they are able to significantly lower the cavitation threshold. However, although NDs were shown to be an effective histotripsy agent, they pose several issues. Their generation requires multistep synthesis, they lack long-term stability, and determination of PFC concentration in the treatment dose is not possible. In this study, PFC-filled nanocones (NCs) were developed as a new generation of histotripsy agents to address the mentioned limitations of NDs. The developed NCs represent an inclusion complex of methylated ß-cyclodextrin as a water-soluble analog of ß-cyclodextrin and perfluorohexane (PFH) as more effective PFC derivatives for histotripsy. Results showed that NCs are easy to produce, biocompatible, have a size <50 nm, and have a quantitative complexation that allows us to directly calculate the PFH amount in the used NC dose. Results further demonstrated that NCs embedded into tissue-mimicking phantoms generated histotripsy cavitation "bubble clouds" at a significantly lower transducer amplitude compared to control phantoms, demonstrating the ability of NCs to function as effective histotripsy agents for NMH.

Nanoparticle-mediated histotripsy (NMH) using perfluorohexane 'nanocones'.

Nanoparticle-mediated histotripsy (NMH) is an ultrasound treatment strategy that combines acoustically sensitive nanoparticles with histotripsy. Previous NMH studies using perfluorocarbon (PFC) nanodroplets (ND's), ~200 nm in diameter, demonstrated that NMH can selectively generate cavitation by reducing the cavitation threshold from ~25-30 MPa to ~10-15 MPa. Recent studies have also shown that cavitation nucleation in NMH is directly caused by the incident negative pressure (p-) exposed to the PFC, as predicted by classical nucleation theory (CNT), suggesting that the NMH cavitation threshold is dependent on the total volume of PFC present in the focal region. In this study, we investigate the use of a newly developed NMH nanoparticle synthesized using an inclusion complex of methylated ß-cyclodextrin and perfluorohexane (PFH). These 'nanocones' (NCs) have advantages compared to previously used ND's due to their smaller size (~50 nm), simple synthesis method, higher stability and information of definite PFH amount carried by the NC. To test the hypothesis that NCs can reduce the NMH cavitation threshold similar to ND's, and that the NMH cavitation threshold is dependent upon the total PFH concentration, tissue phantoms containing concentrations of NCs ranging from 10-5 to 10-10 (ml PFH/ml water) were exposed to single cycle ultrasound pulses using a 500 kHz focused transducer where high speed imaging captured cavitation data. Results showed that NCs significantly reduced the histotripsy cavitation threshold to 11.0 MPa for a concentration of 10-5 (ml PFH/ml water), with the threshold increasing at lower concentrations. Finally, the ability of NCs to be used for effective NMH ablation was demonstrated in tissue phantoms containing red blood cells (RBCs). Overall, the results of the study support our hypotheses that NCs can be used for effective NMH therapy and that NC concentration has a predictable threshold-reducing effect.

The potential of imaging techniques as a screening tool for colorectal cancer: a cost-effectiveness analysis.

OBJECTIVE: Imaging may be promising for colorectal cancer (CRC) screening, since it has test characteristics comparable with colonoscopy but is less invasive. We aimed to assess the potential of CT colonography (CTC) and MR colonography (MRC) in terms of (cost-effectiveness) using the Adenoma and Serrated pathway to Colorectal CAncer model. METHODS: We compared several CTC and MRC strategies with 5- or 10-yearly screening intervals with no screening, 10-yearly colonoscopy screening and biennial faecal immunochemical test (FIT) screening. We assumed trial-based participation rates in the base-case analyses and varied the rates in sensitivity analyses. Incremental lifetime costs and health effects were estimated from a healthcare perspective. RESULTS: The health gain of CTC and MRC was similar and ranged from 0.031 to 0.048 life-year gained compared with no screening, for 2-5 screening rounds. Lifetime costs per person for MRC strategies were €60-110 higher than those for CTC strategies with an equal number of screening rounds. All imaging-based strategies were cost-effective compared with no screening. FIT screening was the dominant screening strategy, leading to most LYG and highest cost-savings. Compared with three rounds of colonoscopy screening, CTC with five rounds was found to be cost-effective in an incremental analysis of imaging strategies. Assumptions on screening participation have a major influence on the ordering of strategies in terms of costs and effects. CONCLUSION: CTC and MRC have potential for CRC screening, compared with no screening and compared with three rounds of 10-yearly colonoscopy screening. When taking FIT screening as the reference, imaging is not cost-effective. Participation is an important driver of effectiveness and cost estimates. ADVANCES IN KNOWLEDGE: This is the first study to assess the cost-effectiveness of MRC screening for CRC.

Long-Term Impact of the Dutch Colorectal Cancer Screening Program on Cancer Incidence and Mortality-Model-Based Exploration of the Serrated Pathway.

BACKGROUND: We aimed to predict the long-term colorectal cancer incidence, mortality, and colonoscopy demand of the recently implemented Dutch colorectal cancer screening program. METHODS: The Adenoma and Serrated pathway to Colorectal Cancer model was set up to simulate the Dutch screening program consisting of biennial fecal immunochemical testing combined with the new Dutch surveillance guidelines, between 2014 and 2044. The impact of screening and surveillance was evaluated under three sets of natural history assumptions differing in the contribution of the serrated pathway to colorectal cancer incidence. In sensitivity analyses, other assumptions concerning the serrated pathway were varied. Model-predicted outcomes were yearly colorectal cancer incidence, mortality, and colonoscopy demand per year. RESULTS: Assuming an aging population, colorectal cancer incidence under 30 years of screening is predicted to decrease by 35% and 31% for a contribution of 0% and 30% of the serrated pathway to colorectal cancer, respectively. For colorectal cancer mortality, reductions are 47% and 45%. In 2044, 110,000 colonoscopies will be required annually assuming no contribution of the serrated pathway (27 per 1,000 individuals in the screening age range). Including the serrated pathway influences predicted screening effectiveness if serrated lesions are neither detected nor treated at colonoscopy, and/or if colorectal cancers arising from serrated lesions have substantially lower survival rates than those arising from adenomas. CONCLUSIONS: The Dutch screening program will markedly decrease colorectal cancer incidence and mortality but considerable colonoscopy resources will be required. IMPACT: Predictions of long-term screening effectiveness are preferably based on both pathways to colorectal cancer to transparently describe the impact of uncertainties regarding the serrated pathway on long-term predictions.

Cost-effectiveness of cervical cancer prevention in Central and Eastern Europe and Central Asia.

We studied the cost-effectiveness of cervical cancer prevention strategies in the Central and Eastern Europe and Central Asia (CEECA) region. The cost-effectiveness of human papillomavirus (HPV)16/18 vaccination of 12 year-old girls was calculated for 28 countries, under the assumption that vaccination prevents 70% of all cervical cancer cases and that cervical cancer and all-cause mortality rates are stable without vaccination. At three-dose vaccination costs of I$ 100 per vaccinated girl (currency 2005 international dollars), HPV16/18 vaccination was very cost-effective in 25 out of 28 countries using the country's gross domestic product (GDP) per capita as cost-effectiveness threshold (criterion by World Health Organization). A three-dose vaccination cost of I$ 100 is within the current range of vaccine costs in European immunization programs, and therefore our results indicate that HPV vaccination may be good value for money. To evaluate the cost-effectiveness of cervical cancer screening combined with vaccination, we calibrated a published simulation model to HPV genotype data collected in Slovenia, Poland, and Georgia. The screening interval was varied at 3, 6, and 10 years starting at age 25 or 30 and ending at age 60. In Slovenia and Poland, combined vaccination and 10-yearly HPV (DNA) screening (vaccination coverage 70%, screening coverage per round 70%) was very cost-effective when the cost of three-dose vaccination was I$ 100 per vaccinated girl. More intensive screening was very cost-effective when the screening coverage per round was 30% or 50%. In Georgia, 10-yearly Pap screening was very cost-effective in unvaccinated women. Vaccination combined with 10-yearly HPV screening was likely to be cost-effective if the three-dose vaccination cost was I$ 50 per vaccinated girl. To conclude, cervical cancer prevention strategies utilizing both HPV16/18 vaccination and HPV screening are very cost-effective in countries with sufficient resources. In low-resource settings, low vaccine pricing is essential for strategies of combined vaccination and screening to be cost-effective. This article forms part of a regional report entitled "Comprehensive Control of HPV Infections and Related Diseases in the Central and Eastern Europe and Central Asia Region" Vaccine Volume 31, Supplement 7, 2013. Updates of the progress in the field are presented in a separate monograph entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.