Penheiter, Alan R.

Key pointsCommon single nucleotide polymorphisms in the beta‐2 adrenoceptor (ADRB2) gene influence cardiovascular function, but they exist in combinations (haplotypes), so it is crucial to characterize the haplotypes to improve the functional predictive power of ADRB2 gene variation.Dietary sodium affects ADRB2 function.In a large randomized cross‐over phenotyping trial that administered low, normal and high dietary sodium, we determined the interactions between ADRB2 haplotype, receptor density on lymphocytes, cardiovascular haemodynamics during stress manoeuvres, forearm blood flow vasodilator responsiveness and dietary sodium.Healthy young adults were recruited based on the homozygous haplotypes of the ADRB2 gene: Arg16+Gln27, the rare Gly16+Gln27 and Gly16+Glu27.Independent of dietary sodium, the Gly16+Glu27 haplotype had the greatest ADRB2 density and Arg16+Gln27 had the least, suggesting that ADRB2 haplotype influences ADRB2 protein expression, yet the haemodynamic consequences appear modest in healthy humans, necessitating larger trials that explore variation in multiple candidate genes.AbstractDietary sodium affects function of the beta‐2 adrenoceptor (ADRB2). We tested the hypothesis that haplotype variation in the ADRB2 gene would influence the cardiovascular and regional vasodilator responses to sympathoexcitatory manoeuvres following low, normal and high sodium diets, and ADRB2‐mediated forearm vasodilation in the high sodium condition. Seventy‐one healthy young adults were grouped by double homozygous haplotypes: Arg16+Gln27 (n = 31), the rare Gly16+Gln27 (n = 10) and Gly16+Glu27 (n = 30). Using a randomized cross‐over design, subjects were studied following 5 days of controlled low, normal and high sodium with 1 month or longer between diets (and low hormone phase of the menstrual cycle). All three visits utilized ECG and finger plethysmography for haemodynamic measures, and the high sodium visit included a brachial arterial catheter for forearm vasodilator responses to isoprenaline with plethysmography. Lymphocytes were sampled forex vivoanalysis of ADRB2 density and binding conformation. We found a main effect of haplotype on ADRB2 density (P = 0.03) with the Gly16+Glu27 haplotype having the greatest density (low, normal, high sodium: 12.9 ± 0.9, 13.5 ± 0.9 and 13.6 ± 0.8 fmol mg−1protein, respectively) and Arg16+Gln27 having the least (9.3 ± 0.6, 10.1 ± 0.5 and 10.3 ± 0.6 fmol mg−1protein, respectively), but there were no sodium or haplotype effects on receptor binding conformation. In the mental stress trial, there was a main effect of haplotype on cardiac output (P = 0.04), as Arg16+Gln27 had the lowest responses. Handgrip and forearm vasodilation yielded no haplotype differences, and no correlations were present for ADRB2 density and haemodynamics. Our findings support cell‐based evidence that ADRB2 haplotype influences ADRB2 protein expression independent of dietary sodium, yet the haemodynamic consequences appear modest in healthy humans.

Abstract RATIONALE: The inability to deliver viruses homogeneously throughout solid tumors is a universal obstacle encountered in oncolytic virotherapy. The initial intratumoral viral dispersion volume is a critical determinant of virotherapy efficacy, and depends not only on the number of infected cells, but also on the spatial distribution of the infected cells. In this study, we determined the feasibility and usefulness of monitoring the initial intratumoral delivery of oncolytic viruses to solid tumors using contrast-enhanced computed tomography (CT). EXPERIMENTAL PROCEDURES: Human BxPC-3 pancreatic tumor xenografts were established in nude mice. An engineered oncolytic measles virus expressing the sodium iodide symporter reporter (MV-NIS) was mixed with a 1:10 dilution of Omnipaque-300 contrast material and injected directly into mouse tumors. Mice were imaged with micro-CT immediately pre and post-injection of the virus + Omnipaque solution and on day 3 post-injection with 99mTcO4 micro-SPECT/CT. Tumors were harvested immediately after micro-SPECT/CT imaging for autoradiography and immunistochemistry analysis of radioactivity uptake and viral infection. Linear regression and Spearman correlation analyses were performed to determine the relationship between intratumoral contrast enhancement and subsequent intratumoral viral infection. RESULTS: This dilution of Omnipaque was found to have no effect on viral infectivity or cell viability in vitro, yet was more than adequate for CT imaging of the virus + Omnipaque injectate distribution following intratumoral injection. Ex vivo autoradiography and immunohistochemistry confirmed a strong correlation between intratumoral CT contrast enhancement, SPECT activity, viral infection, and sodium iodide symporter activity. CONCLUSIONS: This injection method is translatable to the clinic and should allow optimization of intratumoral injection in humans. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4145. doi:10.1158/1538-7445.AM2011-4145

AbstractBackgroundWe aimed to determine the feasibility of monitoring viral delivery and initial distribution to solid tumors using iodinated contrast agent and micro‐computed tomography (CT).MethodsHuman BxPC‐3 pancreatic tumor xenografts were established in nude mice. An oncolytic measles virus with an additional transcriptional unit encoding the sodium iodide symporter (NIS), as a reporter for viral infection, was mixed with a 1:10 dilution of Omnipaque 300 (GE Healthcare, Milwaukee, WI, USA) contrast agent and injected directly into tumors. Mice were imaged with micro‐CT immediately before and after injection to determine the location of contrast agent/virus mixture. Mice were imaged again on day 3 after injection with micro‐single‐photon emission CT/CT to determine the location of NIS‐mediated 99mTcO4 transport.ResultsA 1:10 dilution of Omnipaque had no effect on viral infectivity or cell viability in vitro and was more than adequate for CT imaging of the intratumoral injectate distribution. The volume of tumor coverage with initial CT contrast agent and the 3‐day postinfection measurement of virally infected tumor volume were significantly correlated. Additionally, regions of the tumor that did not receive contrast agent from the initial injection were largely devoid of viral infection at early time points.ConclusionsContrast‐enhanced viral delivery enables a rapid and accurate prediction of the initial viral distribution within a solid tumor. This technique should enable real‐time monitoring of viral propagation from initially infected tumor regions to adjacent tumor regions. Copyright © 2012 John Wiley & Sons, Ltd.