No stone unturned: Nodule Net, an intervention to reduce loss to follow-up of lung nodules

OBJECTIVE

Inadequate lung nodule surveillance leads to diagnostic delays. We implemented a retrospective intervention program, Nodule Net, to improve surveillance in our hospital.

METHODS

9,224 Chest computed tomography (CT) scans between January 1, 2015 and December 31, 2016 were manually reviewed for lung nodules. For patients without follow-up, charts were reviewed to assess follow-up. If follow-up appeared indicated, the clinician or patient was contacted, and follow-up was tracked.

RESULTS

Lung nodules were identified on 5,101 (55%) of 9,224 scans. Follow-up was potentially indicated and not completed in 1,385 (27%). 183 (13%) were excluded after imaging review. 1,202 received outreach. Of the 801 (66%) with a provider in our system, 225 (27%) returned for follow-up. Nodules were stable in 199 (88%), new or growing in 23 (11%), resolved in 3 (1%), and stage 1 lung cancer in 2 (1%). 90 (11%) had follow-up outside our system and 431 (51%) had no follow-up due to a clinical contraindication. 55 (7%) have imaging pending and 14 (2%) are awaiting pulmonary evaluation. Of the 302 (25%) patients with providers outside our system, 121 (40%) had followed-up elsewhere. 146 (48%) had no follow-up due to a clinical reason. 35 (12%) providers did not respond to outreach.

CONCLUSIONS

We identified 1,202 patients with lung nodules who needed follow-up over a two-year period. Compliance was more successful with providers within our hospital system. We recommend robust surveillance for patients to ensure follow-up is completed and clinical contraindications are well documented.

Autofluorescence flow sorting of breast cancer cell metabolism

Clinical cancer treatment aims to target all cell subpopulations within a tumor. Autofluorescence microscopy of the metabolic cofactors NAD(P)H and FAD has shown sensitivity to anti-cancer treatment response. Alternatively, flow cytometry is attractive for high throughput analysis and flow sorting. This study measures cellular autofluorescence in three flow cytometry channels and applies cellular autofluorescence to sort a heterogeneous mixture of breast cancer cells into subpopulations enriched for each phenotype. Sorted cells were grown in culture and sorting was validated by morphology, autofluorescence microscopy, and receptor expression. Ultimately, this method could be applied to improve drug development and personalized treatment planning.

Dysfunctional BMPR2 signaling drives an abnormal endothelial requirement for glutamine in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is increasingly recognized as a systemic disease driven by alteration in the normal functioning of multiple metabolic pathways affecting all of the major carbon substrates, including amino acids. We found that human pulmonary hypertension patients (WHO Group I, PAH) exhibit systemic and pulmonary-specific alterations in glutamine metabolism, with the diseased pulmonary vasculature taking up significantly more glutamine than that of controls. Using cell culture models and transgenic mice expressing PAH-causing BMPR2 mutations, we found that the pulmonary endothelium in PAH shunts significantly more glutamine carbon into the tricarboxylic acid (TCA) cycle than wild-type endothelium. Increased glutamine metabolism through the TCA cycle is required by the endothelium in PAH to survive, to sustain normal energetics, and to manifest the hyperproliferative phenotype characteristic of disease. The strict requirement for glutamine is driven by loss of sirtuin-3 (SIRT3) activity through covalent modification by reactive products of lipid peroxidation. Using 2-hydroxybenzylamine, a scavenger of reactive lipid peroxidation products, we were able to preserve SIRT3 function, to normalize glutamine metabolism, and to prevent the development of PAH in BMPR2 mutant mice. In PAH, targeting glutamine metabolism and the mechanisms that underlie glutamine-driven metabolic reprogramming represent a viable novel avenue for the development of potentially disease-modifying therapeutics that could be rapidly translated to human studies.

In Vivo Autofluorescence Imaging of Tumor Heterogeneity in Response to Treatment

Subpopulations of cells that escape anti-cancer treatment can cause relapse in cancer patients. Therefore, measurements of cellular-level tumor heterogeneity could enable improved anti-cancer treatment regimens. Cancer exhibits altered cellular metabolism, which affects the autofluorescence of metabolic cofactors NAD(P)H and FAD. The optical redox ratio (fluorescence intensity of NAD(P)H divided by FAD) reflects global cellular metabolism. The fluorescence lifetime (amount of time a fluorophore is in the excited state) is sensitive to microenvironment, particularly protein-binding. High-resolution imaging of the optical redox ratio and fluorescence lifetimes of NAD(P)H and FAD (optical metabolic imaging) enables single-cell analyses. In this study, mice with FaDu tumors were treated with the antibody therapy cetuximab or the chemotherapy cisplatin and imaged in vivo two days after treatment. Results indicate that fluorescence lifetimes of NAD(P)H and FAD are sensitive to early response (two days post-treatment, P < .05), compared with decreases in tumor size (nine days post-treatment, P < .05). Frequency histogram analysis of individual optical metabolic imaging parameters identifies subpopulations of cells, and a new heterogeneity index enables quantitative comparisons of cellular heterogeneity across treatment groups for individual variables. Additionally, a dimensionality reduction technique (viSNE) enables holistic visualization of multivariate optical measures of cellular heterogeneity. These analyses indicate increased heterogeneity in the cetuximab and cisplatin treatment groups compared with the control group. Overall, the combination of optical metabolic imaging and cellular-level analyses provide novel, quantitative insights into tumor heterogeneity.

High-throughput measurements of the optical redox ratio using a commercial microplate reader

There is a need for accurate, high-throughput, functional measures to gauge the efficacy of potential drugs in living cells. As an early marker of drug response in cells, cellular metabolism provides an attractive platform for high-throughput drug testing. Optical techniques can noninvasively monitor NADH and FAD, two autofluorescent metabolic coenzymes. The autofluorescent redox ratio, defined as the autofluorescence intensity of NADH divided by that of FAD, quantifies relative rates of cellular glycolysis and oxidative phosphorylation. However, current microscopy methods for redox ratio quantification are time-intensive and low-throughput, limiting their practicality in drug screening. Alternatively, high-throughput commercial microplate readers quickly measure fluorescence intensities for hundreds of wells. This study found that a commercial microplate reader can differentiate the receptor status of breast cancer cell lines (p < 0.05) based on redox ratio measurements without extrinsic contrast agents. Furthermore, microplate reader redox ratio measurements resolve response (p < 0.05) and lack of response (p > 0.05) in cell lines that are responsive and nonresponsive, respectively, to the breast cancer drug trastuzumab. These studies indicate that the microplate readers can be used to measure the redox ratio in a high-throughput manner and are sensitive enough to detect differences in cellular metabolism that are consistent with microscopy results.

In vivo imaging of nanoparticle delivery and tumor microvasculature with multimodal optical coherence tomography

Current imaging techniques capable of tracking nanoparticles in vivo supply either a large field of view or cellular resolution, but not both. Here, we demonstrate a multimodality imaging platform of optical coherence tomography (OCT) techniques for high resolution, wide field of view in vivo imaging of nanoparticles. This platform includes the first in vivo images of nanoparticle pharmacokinetics acquired with photothermal OCT (PTOCT), along with overlaying images of microvascular and tissue morphology. Gold nanorods (51.8 ± 8.1 nm by 15.2 ± 3.3 nm) were intravenously injected into mice, and their accumulation into mammary tumors was non-invasively imaged in vivo in three dimensions over 24 hours using PTOCT. Spatial frequency analysis of PTOCT images indicated that gold nanorods reached peak distribution throughout the tumors by 16 hours, and remained well-dispersed up to 24 hours post-injection. In contrast, the overall accumulation of gold nanorods within the tumors peaked around 16 hours post-injection. The accumulation of gold nanorods within the tumors was validated post-mortem with multiphoton microscopy. This shows the utility of PTOCT as part of a powerful multimodality imaging platform for the development of nanomedicines and drug delivery technologies.

Optical metabolic imaging of treatment response in human head and neck squamous cell carcinoma

Optical metabolic imaging measures fluorescence intensity and lifetimes from metabolic cofactors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD). These molecular level measurements provide unique biomarkers for early cellular responses to cancer treatments. Head and neck squamous cell carcinoma (HNSCC) is an attractive target for optical imaging because of easy access to the site using fiber optic probes. Two HNSCC cell lines, SCC25 and SCC61, were treated with Cetuximab (anti-EGFR antibody), BGT226 (PI3K/mTOR inhibitor), or cisplatin (chemotherapy) for 24 hours. Results show increased redox ratio, NADH α1 (contribution from free NADH), and FAD α1 (contribution from protein-bound FAD) for malignant cells compared with the nonmalignant cell line OKF6 (p<0.05). In SCC25 and SCC61 cells, the redox ratio is unaffected by cetuximab treatment and decreases with BGT226 and cisplatin treatment (p<0.05), and these results agree with standard measurements of proliferation rates after treatment. For SCC25, NADH α1 is reduced with BGT226 and cisplatin treatment. For SCC61, NADH α1 is reduced with cetuximab, BGT226, and cisplatin treatment. Trends in NADH α1 are statistically similar to changes in standard measurements of glycolytic rates after treatment. FAD α1 is reduced with cisplatin treatment (p<0.05). These shifts in optical endpoints reflect early metabolic changes induced by drug treatment. Overall, these results indicate that optical metabolic imaging has potential to detect early response to cancer treatment in HNSCC, enabling optimal treatment regimens and improved patient outcomes.

Association of angiotensin converting enzyme (ACE) gene polymorphism with hypertension in a Bangladeshi population

The association of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with hypertension has not been confirmed. Inconsistencies may be due to the differences of background population characteristics. Till date, there has been no report in Bangladeshi population. This study was to examine the association of ACE (I/D) polymorphism with hypertension. Fifty-one primary hypertensives and fifty-two normotensives were recruited from a hospital in Dhaka city. Height, weight and blood pressure were measured. ACE (I/D) genotypes was established using polymerase chain reaction protocol. The genotype and allele frequencies did not differ significantly (P > 0.05) between the groups. In logistic regression analysis, adjusted for age, sex and body mass index, the genotypes were not associated with hypertension (DD vs II: Adds ratio = 2.6, P = 0.34; ID vs II: 0.4, 0.23; ID + DD vs II: 0.8, 0.69). In this hospital-based sample of Bangladeshi people, significant association of ACE I/D genotype with hypertension was not observed.

Myocardial abscess due to Klebsiella pneumoniae complicating acute infarction

A case is described in which Klebsiella pneumoniae urosepsis associated with acute myocardial infarction resulted in myocardial abscess and papillary muscle rupture. The diagnosis was made during surgery for mitral valve replacement. The patient improved after therapy with cefotaxime; however, cardiac rupture occurred on the sixth postoperative day. The pathogenesis of myocardial abscess and the use of non-invasive techniques for diagnosis are discussed.