Associations of cardiovascular and diabetes-related risk factors with myocardial perfusion reserve assessed by 201Tl/99mTc-tetrofosmin single-photon emission computed tomography in patients with diabetes mellitus and stable coronary artery disease

We aimed to examine the associations of cardiovascular risk factors with myocardial perfusion reserve (MPR) in patients with type 2 diabetes and stable coronary artery disease. The study patients were retrospectively identified from a database of patients with diabetes and stable coronary artery disease at Asan Medical Center (Seoul, Republic of Korea), covering the period from 2017 to 2019. The primary outcome variable was MPR assessed by dynamic stress 201Tl/rest 99mTc-tetrofosmin SPECT. Univariable and stepwise multivariable analyses were performed to assess the associations of cardiovascular risk factors with MPR. A total of 276 patients (236 men and 40 women) were included. The median global MPR was 2.4 (interquartile range 1.9-3.0). Seventy-five (27.2%) patients had an MPR < 2.0. Multivariable linear regression showed that smoking (ß = - 0.44, 95% confidence interval - 0.68 to - 0.21, P < 0.001), hypertension (ß = - 0.24, 95% confidence interval - 0.47 to - 0.02, P = 0.033), and summed difference score (ß = - 0.05, 95% confidence interval - 0.07 to - 0.03, P < 0.001) were independently associated with MPR. Abnormal MPR (< 2.0) was associated with a higher incidence of cardiac death or myocardial infarction (P = 0.034). MPR assessed by dynamic stress 201Tl/rest 99mTc-tetrofosmin SPECT was impaired in a large cohort of patients with diabetes. After adjusting for risk variables, including standard myocardial perfusion imaging characteristics, smoking, and hypertension were associated with MPR. Our results may aid in identifying patients with impaired MPR and stratifying patients with type 2 diabetes.

Prognostic significance of pretreatment 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with T2N1 hormone receptor-positive, ERBB2-negative breast cancer who underwent adjuvant chemotherapy

PURPOSE

To determine whether tumor uptake of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is associated with invasive disease-free survival (IDFS) in patients with hormone receptor (HR)-positive ERBB2-negative early-stage breast cancer treated with adjuvant chemotherapy.

METHODS

This is a single-center cohort study of women with breast cancer who underwent surgery between 2008 and 2015 at Asan Medical Center, Seoul, Korea. Patients were enrolled if they were diagnosed with HR-positive ERBB2-negative breast cancer with histology of invasive ductal carcinoma, had an American Joint Committee on Cancer pathologic tumor stage of T2N1 with 1-3 positive axillary nodes, underwent preoperative ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT), and underwent breast cancer surgery followed by anthracycline- or taxane-based adjuvant chemotherapy. The primary outcome measure was IDFS. The maximum standardized uptake value (SUVmax) was dichotomized using a predefined cut-off of 4.14.

RESULTS

A total of 129 patients were included. The median follow-up period for IDFS in those without recurrence was 82 months (interquartile range, 65-106). Multivariable Cox analysis showed that SUVmax was independently associated with IDFS [adjusted hazard ratio 2.49; 95% confidence interval (CI), 1.06-5.84]. Ten-year IDFS estimates via the Kaplan-Meier method were 0.60 (95% CI, 0.42-0.74) and 0.82 (95% CI, 0.65-0.91) for high and low SUVmax groups, respectively. The overall association between SUVmax and IDFS appeared to be consistent across subgroups divided according to age, progesterone receptor status, histologic grade, or presence of lymphovascular invasion.

CONCLUSION

High SUVmax on preoperative ¹⁸F-FDG PET/CT was independently associated with reduced long-term IDFS in T2N1 HR-positive ERBB2-negative breast cancer patients who underwent adjuvant chemotherapy.

Positron emission tomography imaging of system xc- in immune cells for assessment of disease activity in mice and patients with inflammatory bowel disease

We aimed to explore whether the imaging of antiporter system xC^- of immune cells with (4S)-4-(3-[¹⁸F-fluoropropyl)-L-glutamate (¹⁸F-FSPG) positron emission tomography (PET) can assess inflammatory bowel disease (IBD) activity in murine models and patients (NCT03546868). Methods: ¹⁸F-FSPG PET imaging was performed to assess IBD activity in mice with dextran sulfate sodium-induced and adoptive T-cell transfer-induced IBD and a cohort of 20 patients at a tertiary care center in South Korea. Immunohistochemical analysis of system xC^- and cell surface markers was also studied. Results: Mice with experimental IBD showed increased intestinal ¹⁸F-FSPG uptake and xCT expression in CD11c+, F4/80+, and CD3+ cells in the lamina propria, increases positively associated with clinical and pathological disease activity. ¹⁸F-FSPG PET studies in patients, most of whom were clinically in remission or had mildly active IBD, showed that PET imaging was sufficiently accurate in diagnosing endoscopically active IBD and remission in patients and bowel segments. ¹⁸F-FSPG PET correctly identified all nine patients with superficial or deep ulcers. Quantitative intestinal ¹⁸F-FSPG uptake was strongly associated with endoscopic indices of IBD activity. The number of CD68+xCT+ and CD3+xCT+ cells in 22 bowel segments from patients with ulcerative colitis and the number of CD68+xCT+ cells in seven bowel segments from patients with Crohn's disease showed a significant positive association with endoscopic indices of IBD activity. Conclusion: The assessment of system xC^- in immune cells may provide diagnostic information on the immune responses responsible for chronic active inflammation in IBD. ¹⁸F-FSPG PET imaging of system xC^- activity may noninvasively assess the IBD activity.

Assessment of naive indolent lymphoma using whole-body diffusion-weighted imaging and T2-weighted MRI: results of a prospective study in 30 patients

Background

We prospectively evaluated the diagnostic utility of whole-body diffusion-weighted imaging with background body signal suppression and T2-weighted short-tau inversion recovery MRI (WB-DWIBS/STIR) for the pretherapeutic staging of indolent lymphoma in 30 patients.

Methods

This prospective study included 30 treatment-naive patients with indolent lymphomas who underwent WB-DWIBS/STIR and conventional imaging workup plus biopsy. The pretherapeutic staging agreement, sensitivity, and specificity of WB-DWIBS/STIR were investigated with reference to the multimodality and multidisciplinary consensus review for nodal and extranodal lesions excluding bone marrow.

Results

In the pretherapeutic staging, WB-DWIBS/STIR showed very good agreement (κ = 0.96; confidence interval [CI], 0.88–1.00), high sensitivity (93.4–95.1%), and high specificity (99.0–99.4%) for the whole-body regions. These results were similar to those of ¹⁸F-FDG-PET/CT, except for the sensitivity for extranodal lesions. For extranodal lesions, WB-DWIBS/STIR showed higher sensitivity compared to ¹⁸F-FDG-PET/CT for the whole-body regions (94.9–96.8% vs. 79.6–86.3%, P = 0.058).

Conclusion

WB-DWIBS/STIR is an effective modality for the pretherapeutic staging of indolent lymphoma, and it has benefits when evaluating extranodal lesions, compared with ¹⁸F-FDG-PET/CT.

Regorafenib-Induced Hypothyroidism as a Predictive Marker for Improved Survival in Metastatic or Unresectable Colorectal Cancer Refractory to Standard Therapies: A Prospective Single-Center Study

BACKGROUND

Tyrosine kinase inhibitor-induced hypothyroidism is associated with favorable survival in patients with various cancers.

OBJECTIVE

We aimed to investigate the incidence of regorafenib-induced hypothyroidism and assess its prognostic value in patients with metastatic or unresectable colorectal cancer (CRC) receiving regorafenib.

PATIENTS AND METHODS

This study included 68 patients treated at Asan Medical Center (Seoul, Republic of Korea) between 2014 and 2016 with metastatic or unresectable CRC refractory to standard therapies. Regorafenib (160 mg/day on days 1-21 followed by a 7-day break) was administered.

RESULTS

The median patient age was 58 (range 26-72) years; 61.8% of patients were male. Among the 68 patients, 50 (73.5%) showed hypothyroidism; 39 (57.4%) had subclinical and 11 (16.2%) had symptomatic hypothyroidism. Overall, the objective response rate (ORR) and disease control rate (DCR) were 7.4% and 70.6%, respectively; both were significantly higher in patients with symptomatic or subclinical hypothyroidism than in euthyroid patients (ORR 27.3% vs. 5.1% vs. 0.0%, P = 0.001; DCR 100% vs. 76.9% vs. 38.9%, P = 0.001). Median progression-free survival (PFS) and overall survival (OS) were longer in patients with symptomatic hypothyroidism than in those with subclinical hypothyroidism (median PFS 9.1 vs. 3.8 months, P = 0.018; median OS: 19.2 vs. 9.4 months, P = 0.012) or with euthyroid status (median PFS 9.1 vs. 1.8 months, P < 0.001; median OS 19.2 vs. 4.7 months, P = 0.001). Symptomatic hypothyroidism was a significant protective factor for PFS (hazard ratio (HR) = 0.37, P = 0.006) and OS (HR = 0.35, P = 0.007); no other adverse events were associated with survival.

CONCLUSIONS

Regorafenib-induced hypothyroidism frequently occurs in patients with metastatic CRC receiving regorafenib and is associated with improved survival. Thyroid function status should be actively monitored in CRC patients receiving regorafenib.

Clinical Evaluation of (4S)-4-(3-[18F]Fluoropropyl)-L-glutamate (18F-FSPG) for PET/CT Imaging in Patients with Newly Diagnosed and Recurrent Prostate Cancer

PURPOSE

(4S)-4-(3-[¹⁸F]Fluoropropyl)-L-glutamic acid (¹⁸F-FSPG) is a radiopharmaceutical for PET imaging of system x_C ^- activity, which can be upregulated in prostate cancer. We present data on the first evaluation of patients with newly diagnosed or recurrent prostate cancer with this radiopharmaceutical.

EXPERIMENTAL DESIGN

Ten patients with primary and 10 patients with recurrent prostate cancer were enrolled in this prospective multicenter study. After injection of 300 MBq of ¹⁸F-FSPG, three whole-body PET/CT scans were obtained. Visual analysis was compared with step-section histopathology when available as well as other imaging studies and clinical outcomes. Metabolic parameters were measured semiquantitatively. Expression levels of xCT and CD44 were evaluated by IHC for patients with available tissue samples.

RESULTS

¹⁸F-FSPG PET showed high tumor-to-background ratios with a relatively high tumor detection rate on a per-patient (89%) and per-lobe (87%) basis. The sensitivity was slightly higher with imaging at 105 minutes in comparison with 60 minutes. The maximum standardized uptake values (SUV_max) for cancer was significantly higher than both normal (P < 0.005) and benign pathology (P = 0.011), while there was no significant difference between normal and benign pathology (P = 0.120). In the setting of recurrence, agreement with standard imaging was demonstrated in 7 of 9 patients (78%) and 13 of 18 lesions (72%), and revealed true local recurrence in a discordant case. ¹⁸F-FSPG accumulation showed moderate correlation with CD44 expression.

CONCLUSIONS

¹⁸F-FSPG is a promising tumor imaging agent for PET that seems to have favorable biodistribution and high cancer detection rate in patients with prostate cancer. Further studies are warranted to determine the diagnostic value for both initial staging and recurrence, and how it compares with other investigational radiotracers and conventional imaging modalities.

Comparison of diagnostic sensitivity of [18F]fluoroestradiol and [18F]fluorodeoxyglucose positron emission tomography/computed tomography for breast cancer recurrence in patients with a history of estrogen receptor-positive primary breast cancer

BACKGROUND

To compare the diagnostic sensitivity of [¹⁸F]fluoroestradiol ([¹⁸F]FES) and [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) for breast cancer recurrence in patients with estrogen receptor (ER)-positive primary breast cancer.

METHODS

Our database of consecutive patients enrolled in a previous prospective cohort study to assess [¹⁸F]FES PET/CT was reviewed to identify eligible patients who had ER-positive primary breast cancer with suspected first recurrence at presentation and who underwent [¹⁸F]FDG PET/CT. The sensitivity of qualitative [¹⁸F]FES and [¹⁸F]FDG PET/CT interpretations was assessed, comparing them with histological diagnoses.

RESULTS

Of the 46 enrolled patients, 45 were confirmed as having recurrent breast cancer, while one was diagnosed with chronic granulomatous inflammation. Forty (89%) patients were ER-positive, four (9%) were ER-negative, and one (2%) patient did not undergo an ER assay. The sensitivity of [¹⁸F]FES PET/CT was 71.1% (32/45, 95% CI, 55.7-83.6), while that of [¹⁸F]FDG PET/CT was 80.0% (36/45, 95% CI, 65.4-90.4) with a threshold of positive interpretation, and 93.3% (42/45, 95% CI, 81.7-98.6) when a threshold of equivocal was used. There was no significant difference in sensitivity between [¹⁸F]FES and [¹⁸F]FDG PET/CT (P = 0.48) with a threshold of positive [¹⁸F]FDG uptake, but the sensitivity of [¹⁸F]FDG was significantly higher than [¹⁸F]FES (P = 0.013) with a threshold of equivocal [¹⁸F]FDG uptake. One patient with a benign lesion showed negative [¹⁸F]FES but positive [¹⁸F]FDG uptake.

CONCLUSIONS

The restaging of patients who had ER-positive primary breast cancer and present with recurrent disease may include [¹⁸F]FES PET/CT as an initial test when standard imaging studies are equivocal or suspicious.

Clinicopathological characteristics of primary central nervous system lymphoma with low 18F-fludeoxyglucose uptake on brain positron emission tomography

Primary central nervous system lymphoma (PCNSL) typically shows a strong uptake of F-fludeoxyglucose (FDG) imaged by positron emission tomography (PET). Uncommonly, PCNSL demonstrates a low uptake on FDG PET. We investigated the clinicopathological characteristics of the unusual cases of PCNSL with low FDG uptake.We retrospectively enrolled 104 consecutive patients with newly diagnosed PCNSL who underwent baseline brain FDG PET. The degree of FDG uptake of PCNSL was visually scored by 4 grades (0, ≤contralateral white matter; 1, >contralateral white matter and <contralateral gray matter; 2, = contralateral gray matter; 3, >contralateral gray matter). Grades 0-2 were considered as PCNSL with low uptake. We investigated association of low uptake of PCNSL with the following clinicopathological factors: age, sex, steroid treatment, lactate dehydrogenase level, cerebrospinal fluid protein level, condition of PET scanning, immunohistochemical markers (cluster of differentiation 10 [CD10], B-cell lymphoma 6 [BCL-6], B-cell lymphoma 2 [BCL-2], multiple myeloma oncogene 1 [MUM1], Epstein-Barr virus [EBV] protein, and Ki67), location of lesions, tumor size, multiplicity of lesions, involvement of deep brain structures, and cystic or necrotic appearance of lesions.Of the 104 patients with PCNSL, 14 patients (13.5%) showed PCNSL with low FDG uptake on PET. Among various clinicopathological factors, MUM1 negativity was the only factor associated with low FDG uptake PCNSL by univariate (P = .002) and multivariate analysis (P = .007).This study suggests that the different clinicopathological characteristics between patients with high uptake and low uptake of PCNSL on FDG PET is closely associated with lack of MUM1, a protein known to be a crucial regulator of B-cell development and tumorigenesis.

Prognostic Factors of Quantitative Lymphoscintigraphic Findings in Patients with Breast Cancer-Related Lymphedema

Background: To evaluate the usefulness of quantitative findings of pretherapy lymphoscintigraphy in predicting the effects of complex decongestive therapy (CDT) in patients with upper extremity lymphedema after breast cancer treatment. Methods and Results: We retrospectively analyzed patients with unilateral breast cancer-related lymphedema (BCRL) who underwent pretherapy lymphoscintigraphy and completed 2 weeks of CDT. A total of 18 patients with unilateral BCRL clinical stage II underwent 30-minute sessions of CDT five times per week for 2 weeks. The quantitative asymmetry index (QAI) of the upper extremity, axillary lymph node (LN) uptake, and axillary plus supraclavicular LN uptake from lymphoscintigraphy were calculated. The volume of lymphedema was calculated by percentage excess volume (PEV) at initial and posttreatment. The CDT response was assessed using percentage reduction in excess volume (PREV). Correlation analyses were conducted using Kendall tau rank correlation. There was positive correlation between upper extremity QAI at 2 hours and initial PEV. Negative correlations were found between axillary LN QAI at 1, 2 hours, and initial PEV, and between axillary plus supraclavicular LN QAI at 1, 2 hours, and initial PEV. The PREV showed a positive correlation with axillary LN QAI at 2 hours after injection (tau-b = 0.354, p = 0.041). Conclusion: Quantitative findings of pretherapy lymphoscintigraphy have potential value for use in predicting the response to CDT in patients with upper extremity lymphedema after breast cancer treatment. Using QAIs from lymphoscintigraphy, we could estimate the excess volume of lymphedema.

Radiation dosimetry of [18F]GP1 for imaging activated glycoprotein IIb/IIIa receptors with positron emission tomography in patients with acute thromboembolism

PURPOSE

4-(3S)-3-[5-(2-[¹⁸F]-fluoroethoxy)pyridin-3-yl]-3-[({(3R)-1-[3-(piperidin-4-yl)propanoyl]-piperidin-3-yl}carbonyl)amino]propanoic acid ([¹⁸F]GP1) is a radiotracer developed for targeted imaging of activated platelet glycoprotein IIb/IIIa receptors with positron emission tomography/computed tomography (PET/CT) in acute thromboembolism. We evaluated here radiation dosimetry of [¹⁸F]GP1 in humans.

PROCEDURES

We studied 30 subjects (10 with deep vein thrombosis, 10 with pulmonary embolism, and 10 with arterial thromboembolism) who had signs or symptoms of acute thromboembolism, and were confirmed to have thromboembolic foci by imaging studies. Dynamic whole-body PET/CT images were acquired for up to 140 min after injection of 250 MBq of [¹⁸F]GP1. Radiation absorbed dose and effective dose were calculated using the OLINDA/EXM software.

RESULTS

[¹⁸F]GP1 PET images showed high initial uptake of the tracer in the heart, spleen, kidney, and liver. [¹⁸F]GP1 activity was cleared by hepatobiliary and urinary excretion. The organ receiving the highest radiation absorbed dose (mGy/MBq) was the urinary bladder (0.0884 ± 0.0458), followed by upper large intestine (0.0498 ± 0.0189), small intestine (0.0454 ± 0.0166), and kidneys (0.0350 ± 0.0231). The effective dose (mSv/MBq) was 0.0212 ± 0.0027 (ICRP 103). ED was not significantly different between the three disease groups (p = 0.94). A 45-minute voiding reduced the urinary bladder wall radiation dose to 0.0495 ± 0.0140 mGy/MBq, and effective dose (ICRP 103) to 0.0186 ± 0.0030.

CONCLUSIONS

[¹⁸F]GP1 has favorable radiation dosimetry profile for clinical PET/CT imaging. The ED is comparable to commonly used ¹⁸F PET tracers.

A phase 1, first-in-human study of 18F-GP1 positron emission tomography for imaging acute arterial thrombosis

BACKGROUND

¹⁸F-GP1 is a novel positron emission tomography (PET) tracer that targets glycoprotein IIb/IIIa receptors on activated platelets. The study objective was to explore the feasibility of directly imaging acute arterial thrombosis (AAT) with ¹⁸F-GP1 PET/computed tomography (PET/CT) and to quantitatively assess ¹⁸F-GP1 uptake. Safety, biodistribution, pharmacokinetics and metabolism were also evaluated.

METHODS

Adult patients who had signs or symptoms of AAT or had recently undergone arterial intervention or surgery within 14 days prior to ¹⁸F-GP1 PET/CT were eligible for inclusion. The AAT focus was demonstrated by conventional imaging within the 5 days prior to ¹⁸F-GP1 administration. Whole-body dynamic ¹⁸F-GP1 PET/CT images were acquired for up to 140 min after injection of 250 MBq of ¹⁸F-GP1. Venous plasma samples were analysed to determine ¹⁸F-GP1 clearance and metabolite formation.

RESULTS

Among the ten eligible patients assessed, underlying diseases were abdominal aortic aneurysm with endovascular repair (n = 6), bypass surgery and stent placement (n = 1), endarterectomy (n = 1), arterial dissection (n = 1) and acute cerebral infarction (n = 1). ¹⁸F-GP1 administration and PET/CT procedures were well tolerated, with no drug-related adverse events. All patients showed high initial ¹⁸F-GP1 uptake in the spleen, kidney and blood pool, followed by rapid clearance. Unmetabolised plasma ¹⁸F-GP1 levels peaked at 4 min post-injection and decreased over time until 120 min. The overall image quality was sufficient for diagnosis in all patients and AAT foci were detected in all participants. The ¹⁸F-GP1 uptake in AAT foci remained constant from 7 min after injection and began to separate from the blood pool after 20 min. The median standardised uptake value of AAT was 5.0 (range 2.4-7.9) at 120 min post-injection. The median ratio of standardised uptake value of AAT foci to the mean blood pool activity was 3.4 (range 2.0-6.3) at 120 min.

CONCLUSIONS

¹⁸F-GP1 is a safe and promising novel PET tracer for imaging AAT with a favourable biodistribution and pharmacokinetic profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02864810 , Registered August 3, 2016.

Physical exercise enhances adult cortical plasticity in a neonatal rat model of hypoxic-ischemic injury: Evidence from BOLD-fMRI and electrophysiological recordings

Neuroplasticity is considered essential for recovery from brain injury in developing brains. Recent studies indicate that it is especially effective during early postnatal development and during the critical period. The current study used functional magnetic resonance imaging (fMRI) and local field potential (LFP) electrophysiological recordings in rats that experienced neonatal hypoxic-ischemic (HI) injury during the critical period to demonstrate that physical exercise (PE) can improve cortical plasticity even when performed during adulthood, after the critical period. We investigated to what extent the blood oxygen level-dependent (BOLD)-fMRI responses were increased in the contralesional spared cortex, and how these increases were related to the LFP electrophysiological measurements and the functional outcome. The balance of excitation and inhibition was assessed by measuring excitatory and inhibitory postsynaptic currents in stellate cells in the primary somatosensory (S1) cortex, which was compared with the BOLD-fMRI responses in the contralesional S1 cortex. The ratio of inhibitory postsynaptic current (IPSC) to excitatory postsynaptic current (EPSC) at the thalamocortical (TC) input to the spared S1 cortex was significantly increased by PE, which is consistent with the increased BOLD-fMRI responses and improved functional outcome. Our data clearly demonstrate in an experimental rat model of HI injury during the critical period that PE in adulthood enhances neuroplasticity and suggest that enhanced feed-forward inhibition at the TC input to the S1 cortex might underlie the PE-induced amelioration of the somatosensory deficits caused by the HI injury. In summary, the results of the current study indicate that PE, even if performed beyond the critical period or during adulthood, can be an effective therapy to treat neonatal brain injuries, providing a potential mechanism for the development of a potent rehabilitation strategy to alleviate HI-induced neurological impairments.

Glycoprotein IIb/IIIa receptor imaging with 18F-GP1 positron emission tomography for acute venous thromboembolism: an open-label, non-randomized, first-in-human phase 1 study

18F-GP1 is a derivative of elarofiban with a high affinity to activated platelet glycoprotein IIb/IIIa (GPIIb/IIIa) and favorable in vivo characteristics for thrombus imaging in preclinical models. We aimed to explore the detection rate of thromboembolic foci with 18F-GP1 positron emission tomography/computed tomography (PET/CT) in patients with acute venous thromboembolism (VTE), and to evaluate the safety, biodistribution, pharmacokinetics, and metabolism of 18F-GP1. Methods: We studied patients who had signs or symptoms of acute deep vein thrombosis (DVT) of the leg or acute pulmonary embolism (PE) within 14 days prior to 18F-GP1 PET/CT, and had thromboembolic foci confirmed by conventional imaging (n = 10 for DVT and n = 10 for PE). Dynamic whole-body PET/CT images were acquired for up to 140 minutes after injection of 250 MBq of 18F-GP1. Results:18F-GP1 PET/CT was well tolerated without any drug-related adverse events, and showed high initial uptake in spleen, kidney, and blood pool, followed by rapid clearance. The overall image quality was excellent and allowed interpretation in all patients. 18F-GP1 PET/CT identified thromboembolic foci in all 20 patients with either DVT or PE. Vessel-level analysis revealed that 18F-GP1 PET/CT detected 89% (68/76) of vessels with DVT, and 60% (146/245) for PE. Importantly, 18F-GP1 PET/CT showed increased uptake in 32 vessels that were not detected by conventional imaging, of which 25 were located in distal veins of the lower extremity in 12 patients. A positive correlation was found between 18F-GP1 uptake and P-selectin-positive circulating platelets (r = 0.656, P = 0.002). Conclusion:18F-GP1 is a promising PET tracer for imaging acute VTE in patients. 18F-GP1 PET/CT may identify thrombi in distal veins of the leg, where conventional imaging has limitations.

microRNA-155 positively regulates glucose metabolism via PIK3R1-FOXO3a-cMYC axis in breast cancer

MicroRNA is an endogenous, small RNA controlling multiple target genes and playing roles in various biological processes including tumorigenesis. Here, we addressed the function of miR-155 using LC-MS/MS-based metabolic profiling of miR-155 deficient breast cancer cells. Our results revealed the loss of miR-155 hampers glucose uptake and glycolysis, via the down-regulation of glucose transporters and metabolic enzymes including HK2, PKM2, and LDHA. We showed this is due to the down-regulation of cMYC, controlled through phosphoinositide-3-kinase regulatory subunit alpha (PIK3R1)-PDK1/AKT-FOXO3a pathway. UTR analysis of the PIK3R1 and FOXO3a indicated miR-155 directly represses these genes. A stable expression of miR-155 in patient-derived cells (PDCs) showed activated glucose metabolism whereas a stable inhibition of miR-155 reduced in vivo tumor growth with retarded glucose metabolism. Furthermore, analysis of 50 triple-negative breast cancer (TNBC) specimens and specific uptake value (SUV) of PET images revealed a positive correlation between miR-155 level and glucose usage in human breast tumors via PIK3R1-PDK/AKT-FOXO3a-cMYC axis. Collectively, these data demonstrate the miR-155 is a key regulator of glucose metabolism in breast cancer.

[18F]fluorothymidine PET Informs the Synergistic Efficacy of Capecitabine and Trifluridine/Tipiracil in Colon Cancer

In cancer therapy, enhanced thymidine uptake by the salvage pathway can bypass dTMP depletion, thereby conferring resistance to thymidylate synthase inhibition. We investigated whether sequential combination therapy of capecitabine and trifluridine/tipiracil (TAS-102) could synergistically enhance antitumor efficacy in colon cancer xenograft models. We also examined 3'-deoxy-3'-[¹⁸F]fluorothymidine ([¹⁸F]FLT) PET as a means to predict therapeutic response to a sequential combination of capecitabine and trifluridine/tipiracil. [³H]FLT uptake after 5-fluorouracil treatment in vitro and [¹⁸F]FLT uptake after capecitabine (360 mg/kg/day) in athymic nude mice (Balb/c-nu) with xenografts (n = 10-12 per group) were measured using eight human colon cancer cell lines. We determined the synergistic effects of sequential combinations of 5-fluorouracil and trifluridine in vitro as well as the sequential combination of oral capecitabine (30-360 mg/kg) and trifluridine/tipiracil (trifluridine 75 or 150 mg/kg with tipiracil) in six xenograft models (n = 6-10 per group). We observed significant increases in [³H]FLT uptake in all cell lines and [¹⁸F]FLT uptake in five xenograft models after 5-fluorouracil and capecitabine treatment, respectively. Increased [¹⁸F]FLT uptake after capecitabine followed by extinction of uptake correlated strongly with tumor growth inhibition (ρ = -0.81, P = 0.02). The effects of these combinations were synergistic in vitro A synergy for sequential capecitabine and trifluridine/tipiracil was found only in mouse xenograft models showing increased [¹⁸F]FLT uptake after capecitabine. Our results suggest that the sequential combination of capecitabine and trifluridine/tipiracil is synergistic in tumors with an activated salvage pathway after capecitabine treatment in mice, and [¹⁸F]FLT PET imaging may predict the response to capecitabine and the synergistic antitumor efficacy of a sequential combination of capecitabine and trifluridine/tipiracil. Cancer Res; 77(24); 7120-30. ©2017 AACR.

Predictors of Renal Functional Improvement After Pyeloplasty in Ureteropelvic Junction Obstruction: Clinical Value of Visually Assessed Renal Tissue Tracer Transit in 99mTc-mercaptoacetyltriglycine Renography

OBJECTIVE

To determine the clinical value of visually assessed renal tissue transit time (TTT) in ^99mTc-mercaptoacetyltriglycine (^99mTc-MAG3) renography for patients undergoing pyeloplasty.

MATERIALS AND METHODS

Medical records of 164 patients who underwent dismembered pyeloplasty were retrospectively reviewed. Baseline and postoperative renal ultrasonography and ^99mTc-MAG3 renography were performed. Two urologists blinded to clinical data evaluated the renography and classified TTT as timely or delayed based on visualization of the tracer in the kidney pelvis between 2 and 10 minutes. Renal functional change after pyeloplasty was compared between patients in the timely and delayed groups.

RESULTS

A total of 126 patients (median age, 9 months) were evaluated after excluding patients with bilateral ureteropelvic junction obstruction, a single functioning kidney, duplicated ureter, or <3 months of follow-up. There were no differences between 89 patients with timely TTT and 37 patients with delayed TTT in mean preoperative hydronephrosis grade (3.7 vs 3.8) and pelvic diameter (3.1 cm vs 3.4 cm). Although the pre- and postoperative mean values of differential renal function (DRF) were significantly higher in the timely group than in the delayed group (47.2% vs 38.3% and 47.9% vs 44.6%), DRF change was greater in the delayed group (6.3% vs 0.6%). In multivariate analysis, delayed TTT was the only significant predictor of >5% improvement in renal function after pyeloplasty.

CONCLUSION

Delayed TTT in ^99mTc-MAG3 renography was a significant predictor of renal functional improvement after pyeloplasty in ureteropelvic junction obstruction. Because substantial improvement of renal function is anticipated, we recommend immediate pyeloplasty in patients with delayed TTT and decreased DRF.

Spatiotemporal microstructural white matter changes in diffusion tensor imaging after transient focal ischemic stroke in rats

Structural reorganization in white matter (WM) after stroke is a potential contributor to substitute or to newly establish the functional field on the injured brain in nature. Diffusion tensor imaging (DTI) is an imaging modality that can be used to evaluate damage and recovery within the brain. This method of imaging allows for in vivo assessment of the restricted movements of water molecules in WM and provides a detailed look at structural connectivity in the brain. For longitudinal DTI studies after a stroke, the conventional region of interest method and voxel-based analysis are highly dependent on the user-hypothesis and parameter settings for implementation. In contrast, tract-based spatial statistics (TBSS) allows for reliable voxel-wise analysis via the projection of diffusion-derived parameters onto an alignment-invariant WM skeleton. In this study, spatiotemporal WM changes were examined with DTI-derived parameters (fractional anisotropy, FA; mean diffusivity, MD; axial diffusivity, DA; radial diffusivity, RD) using TBSS 2 h to 6 weeks after experimental focal ischemic stroke in rats (N = 6). FA values remained unchanged 2-4 h after the stroke, followed by a continuous decrease in the ipsilesional hemisphere from 24 h to 2 weeks post-stroke and gradual recovery from the ipsilesional corpus callosum to the external capsule until 6 weeks post-stroke. In particular, the fibers in these areas were extended toward the striatum of the ischemic boundary region at 6 weeks on tractography. The alterations of the other parameters in the ipsilesional hemisphere showed patterns of a decrease at the early stage, a subsequent pseudo-normalization of MD and DA, a rapid reduction of RD, and a progressive increase in MD, DA and RD with a decreased extent in the injured area at later stages. The findings of this study may reflect the ongoing processes on tissue damage and spontaneous recovery after stroke.

Comparison of MRI and PET-CT in detecting the loco-regional recurrence of soft tissue sarcomas during surveillance

OBJECTIVE

To investigate the diagnostic performance of MRI and PET-CT for the detection of loco-regional recurrences after soft tissue sarcoma (STS) excision.

MATERIALS AND METHODS

From Dec 2003 to Aug 2014, 394 patients with STSs, who were included in the electronic patient registry for initial or repeated surgery at our hospital, were retrospectively reviewed. We identified 152 patients who underwent regular postoperative follow-ups with both MRI and PET-CT, obtained within a 3 month period of each other. We analyzed differences in the performance of MRI and PET-CT for the diagnosis of loco-regional recurrences using McNemar's test. The receiver-operating characteristic curves and calculations of the area under the curve were used.

RESULTS

Twenty patients were found to have a loco-regional recurrence after tumor excision. For MRI and PET-CT, the sensitivities were 90.0 and 95.0 %, and the specificities 97.7 and 95.5 %, respectively, with positive predictive values of 85.7 and 76.0 % and negative predictive values of 98.5 and 99.2 %, respectively. No significant difference was detected between the sensitivities of MRI and PET-CT (p = 0.125). The area under the receiver-operating characteristic curve for PET-CT (0.952) was not significantly greater than that for MRI (0.939; p = 0.6).

CONCLUSION

MRI of the area of interest is recommended for evaluation of tumor recurrence after surgical excision of STS. PET-CT was shown to be effective for detection of STS recurrence, and comparable to MRI. However, if PET-CT or MRI findings are inconclusive, the other modality may be helpful in differentiating tumor recurrence from post-therapeutic tissue change.

Exploratory Clinical Investigation of (4S)-4-(3-18F-Fluoropropyl)-L-Glutamate PET of Inflammatory and Infectious Lesions

We explored system [Formula: see text] transporter activity and the detection of inflammatory or infectious lesions using (4S)-4-(3-(18)F-fluoropropyl)-l-glutamate ((18)F-FSPG) PET.

METHODS

In 10 patients with various inflammatory or infectious diseases, as many as 5 of the largest lesions were selected as reference lesions. (18)F-FSPG images were assessed visually and quantitatively. Expression levels of xCT, CD44, and surface markers of inflammatory cells were evaluated by immunohistochemistry.

RESULTS

(18)F-FSPG PET detected all reference lesions. (18)F-FSPG uptake in sarcoidosis was significantly higher than that in nonsarcoidosis. The lesion-to-blood-pool SUV ratio for (18)F-FSPG was comparable to that for (18)F-FDG in sarcoidosis. In nonsarcoidosis, however, it was significantly lower. In 5 patients with available tissue samples, the SUVmax for (18)F-FSPG and CD163 were negatively correlated (ρ = -0.872, P = 0.054).

CONCLUSION

(18)F-FSPG PET may detect inflammatory lesions when activated macrophages or monocytes are present, such as in sarcoidosis.

Association Between (18)F-FDG Avidity and the BRAF Mutation in Papillary Thyroid Carcinoma

PURPOSE

The BRAF mutation, a potential prognostic factor in papillary thyroid carcinoma (PTC), is associated with a high expression of the glucose transporter gene. We investigated which clinicopathologic factors, including BRAF mutation status, influence (18)F-fluoro-2-deoxyglucose ((18)F-FDG) avidity.

METHODS

We retrospectively reviewed 55 patients who underwent BRAF analysis from biopsy-confirmed PTC and (18)F-FDG positron emission tomography/computed tomography within 6 months before undergoing thyroid surgery from September 2008 to August 2014. Tumors were considered to be (18)F-FDG avid if the uptake was greater than that of the liver. (18)F-FDG uptake of PTCs was also analyzed semiquantitatively using SUVmax. The association between (18)F-FDG avidity and clinicopathologic variables (age, tumor size, perithyroidal extension, cervical lymph node status, and BRAF mutation status) was investigated.

RESULTS

Twenty-nine (52.7 %) of 55 patients had (18)F-FDG-avid PTCs. PTCs with the BRAF mutation showed higher (18)F-FDG avidity (24/38, 63.2 %) than those without (5/17, 29.4 %). The BRAF mutation (p = 0.025) and tumor size (p = 0.003) were significantly associated with (18)F-FDG avidity in univariate analysis, and the BRAF mutation status remained significant after adjusting for tumor size in multivariate analysis (p = 0.015). In the subgroup of tumor size ≥ 1 cm, the BRAF mutation was the only factor significantly associated with (18)F-FDG avidity (p = 0.021). The mean SUVmax of PTCs with the BRAF mutation was significantly higher than that of those without (4.89 ± 6.12 vs. 1.96 ± 1.10, p = 0.039).

CONCLUSIONS

The BRAF mutation must be one of the most important factors influencing (18)F-FDG avidity in PTCs, especially in those with a tumor size ≥ 1 cm.

High-intensity focused ultrasound-induced, localized mild hyperthermia to enhance anti-cancer efficacy of systemic doxorubicin: an experimental study

The aim of this study was to evaluate the enhancement of the efficacy of systemic doxorubicin by pulsed high-intensity focused ultrasound (HIFU)-induced, localized mild hyperthermia. For the in vitro study, the intranuclear uptake of doxorubicin by squamous cell carcinoma (SCC)-7 cells incubated at different temperatures was compared. For the in vivo study, mice with SCC-7 tumors were assigned to either the control, conventional hyperthermia, HIFU hyperthermia, doxorubicin-alone, conventional hyperthermia + doxorubicin or HIFU hyperthermia + doxorubicin group. Conventional hyperthermia was induced by immersing the tumor in warm water (42.5°C), and HIFU hyperthermia was induced by HIFU after optimizing the parameters with direct temperature measurements (frequency = 1 MHz, pulse repetition frequency = 5 Hz, power = 12 W, duty cycle = 50%). In the in vitro study, fluorescence was more intense at 42°C than at 37°C and was time dependent. In the in vivo study, tumor growth in the HIFU hyperthermia + doxorubicin group was most prominently suppressed with the highest apoptotic index compared with all other groups (p < 0.05). Pulsed HIFU-induced localized mild hyperthermia enhanced the anti-cancer efficacy of systemic doxorubicin more than conventional mild hyperthermia.

A case of xanthoma disseminatum: evaluation and monitoring by 18F-fluorodeoxyglucose positron emission tomography/computed tomography

Xanthoma disseminatum (XD) is a rare benign histiocytic disorder with extensive mucocutaneous xanthomas that often involves other sites such as the central nervous system (CNS), respiratory tract and abdominal organs. Evaluation of the extent of disease is important because lesions in critical locations may increase morbidity and mortality. However, there are no well-established tools for the evaluation and monitoring of XD. Here, we report a case of XD in a 21-year-old male patient showing skin, mucous membrane, CNS and internal organ involvement. In this case, (18) F-fluorodeoxyglucose positron emission tomography/computed tomography was useful in detecting the extent of the disease and in estimating the therapeutic response.

Pulsed high-intensity focused ultrasound therapy enhances targeted delivery of cetuximab to colon cancer xenograft model in mice

Our aim was to evaluate whether pulsed high-intensity focused ultrasound (HIFU) therapy enhances the effect of an epidermal growth factor receptor-targeted chemotherapeutic drug, cetuximab, in treating human colon cancer xenografts in a mouse model. Balb/c nude mice with subcutaneous xenografts of HT-29 cells were randomly categorized into control (n = 9), pulsed HIFU alone (n = 10), cetuximab monotherapy (n = 8) or combined pulsed HIFU and cetuximab therapy (n = 9) group. Cetuximab, pulsed HIFU therapy, or both were administered three times per week starting from day 8 after tumor cell injection. Based on tumor growth curves up to 34 days, the combination therapy group showed more suppressed tumor growth than all other groups (p < 0.05). The final relative tumor volumes were 5.4 ± 2.1, 5.2 ± 1.3, 4.8 ± 1.8, and 3.1 ± 0.9 for control, pulsed HIFU alone, cetuximab monotherapy, and combination therapy groups, respectively. In conclusion, pulsed HIFU therapy appears to enhance the anti-tumor effect of epidermal growth factor receptor-targeted cetuximab on human colon cancer xenograft models in mice.

PEGylation improves the hypoglycaemic efficacy of intranasally administered glucagon-like peptide-1 in type 2 diabetic db/db mice

AIMS

PEGylation - covalent modification of therapeutic peptides with polyethylene glycol (PEG) - is viewed as an effective way of prolonging the short lifetime of glucagon-like peptide-1 (GLP-1). In this study, we investigated the hypoglycaemic efficacies of PEGylated GLP-1s administered intranasally in type 2 diabetic db/db mice.

METHODS

Three types of site-specific (Lys(34)) PEGylated GLP-1 analogues (PEG molecular weight: 1, 2 or 5 kDa) were synthesized. Their metabolic stabilities were evaluated in nasal mucosa enzyme pools. Oral glucose tolerance test was conducted 30, 60 and 120 min after intranasally administering these analogues in type 2 diabetic db/db mice.

RESULTS

PEGylated GLP-1 analogues were found to have significantly longer half-lives than native GLP-1 in nasal mucosa enzymes (2.4-fold to 11.0-fold, p < 0.005). Non-PEGylated GLP-1 at 100 nmol/kg was not found to have marked efficacy irrespective of nasal administration time [total hypoglycaemic degree (HD(total)) values 2.8-17.3%]. On the contrary, PEGylated GLP-1s (100 nmol/kg) showed obvious efficacies with maximum HD(total) values of >51.8 +/- 5.8% (p < 0.005 vs. GLP-1).

CONCLUSION

This study highlights the pharmacological potential of intranasally administered PEGylated GLP-1s in terms of stabilizing postprandial hyperglycaemia in type 2 diabetic patients.

Bioactive polymers for biohybrid artificial pancreas

To address the solution for some of the obstacles, such as low insulin secretion, limited lifespan and aggregation of transplanted islets, encountered in developing a biohybrid artificial pancreas (BAP), polymeric materials including a reversible polymeric extracellular matrix (ECM), crystallized glucagon-like peptide-1, and oxygen carrying polymers, were prepared and their potential utilities in designing a compact and rechargeable BAP were investigated. For a synthetic, reversible ECM, high molecular weight N-isopropylacrylamide copolymer with a small amount of acrylic acid (2 mole%) was synthesized by conventional radical polymerization in benzene, and its aqueous solution above a critical polymer concentration displayed a sol-gel transition temperature near physiological temperature (33-35 degrees C) without noticeable hysteresis. The physicochemical properties of the gel with islet compatibility proved that the synthetic ECM is an appropriate matrix which can make a BAP rechargeable. Glucagon-like peptide-1 (GLP-1, 7-37) is known to have a strong stimulatory effect on insulin secretion, particularly at high glucose concentrations. When zinc-crystallized GLP-1 was entrapped along with islets in a hollow fiber macrocapsule device, insulin secretion was enhanced at a high glucose concentration (300 mg/dl) with a >85% increase in insulin secretion after an induction period. The cross-linked hemoglobin with difunctional PEO (Hb-C) was prepared to increase the high molecular weight of Hb. This prevents diffusional loss when enclosed in an immunoprotecting membrane. The Hb-C, entrapped in microcapsules, enhanced insulin secretion and improved the viability of microencapsulated islets by promoting oxygen supply to islets. The introduction of the synthetic ECM, crystallized GLP-1, and Hb-C into a BAP may provide a basis for designing a compact and rechargeable BAP (macrocapsule).

Synthesis of sulfonylurea conjugated copolymer via PEO spacer and its in vitro short-term bioactivity in insulin secretion from islets of Langerhans

In order to reduce the number of immunoprotected islets required in xeno- or allogenic transplants for reversing diabetes, analogues of glyburide (a sulfonylurea), an extremely hydrophobic insulin secretagogue, were synthesized and used in an attempt to produce water soluble sulfonylurea (SU) grafted polymers. After synthesizing various polymers containing glyburide analogues, a poly(N-vinyl-2-pyrrolidone-co-sulfonylurea succinyl PEO (Mw = 3000) acrylate) was found to be soluble in a cell culture medium at pH 7.4. However, solubility was only obtained by decreasing solution pH from 11 to 7.4. When the copolymer was added to the islet cell culture media at a concentration of 5 microg ml(-1) (based on the theoretical SU content of the copolymer), insulin secretion was enhanced by about 30% at low glucose concentrations of 50 and 100 mg dl(-1) compared to the control. This is equivalent to 40-60% bioactivity of glyburide. The polymer's effect on insulin secretion at a higher glucose concentration of 200 mg dl(-1) was not significant. Considering the previous results where a similar but insoluble polymer without a PEO spacer was used and the polymer showed SU bioactivity only at a glucose concentration of 50 mg dl(-1), the observations from this study indicates that the solubility of SU-grafted polymers may affect the binding of SU groups to SU receptors on the pancreatic beta-cells, resulting in improved pharmacodynamic effect of SU.

Vestibulo-ocular reflex in eccentric rotation in squirrel monkeys

In addition to angular acceleration, eccentric rotation (ECR) imparts linear acceleration to the head positioned eccentric to the axis of rotation. Using ECR in squirrel monkeys, the effects of otolith organ stimulation by linear acceleration on vestibulo-ocular reflex (VOR) gain were investigated. With the animal's head facing away from the rotation axis, ECR significantly enhanced VOR gain over that seen in centric rotation (CR) at 1.0 Hz, but not at 0.5 Hz. However, no enhancement of VOR gain at 1.0 Hz was observed in eccentriclateral rotation when the animal faced tangentially. After bilateral ablation of the otolith organs (sacculectomy and utricular neurectomy), the ECR did not increase VOR gain, even at 1.0 Hz. In animals in which the lateral and posterior semicircular canals were plugged bilaterally, horizontal sinusoidal eye movements were induced by ECR at 1.0 Hz; no clear compensatory eye movement occurred during CR at 1.0 Hz. These findings demonstrate that during ECR, tangential acceleration along the interaural axis stimulates the utricular maculae, inducing horizontal eye movements in addition to those induced by the semicircular canal, thus resulting in an enhancement of VOR gain. Our results also suggest synergistic interactions of the otolith organs and semicircular canals. We conclude that ECR is a useful clinical test of the function of the otolith organs.

Effects of otolith stimulation in eccentric rotation on the vestibulo-ocular reflex in squirrel monkeys

When a subject is rotated around an axis located behind his head (eccentric rotation, ECR), he experiences a combination of angular acceleration and two kinds of linear accelerations, tangential and centrifugal. The effects of stimulation of the otolith organs by linear acceleration in ECR on gain of the vestibulo-ocular reflex (VOR) were examined in squirrel monkeys. The VOR gain in ECR with the animal's head facing away from the rotation axis was significantly higher than that in centric rotation (CR) at 1.0 Hz, but not at 0.5 Hz. However, the VOR gain did not increase in eccentric-lateral rotation when the animal faced tangentially, even at 1.0 Hz. After bilateral ablation of the otolith organs (sacculectomy and utricular neurectomy), the VOR gain in ECR did not increase, even at 1.0 Hz. These findings demonstrate that tangential acceleration along the interaural axis in ECR stimulates the utricular maculae, resulting in enhancement of the VOR gain. The results also suggest that ECR is a useful clinical test for the function of the otolith organs.

Recovery of the otolith-ocular reflex after unilateral deafferentation of the otolith organs in squirrel monkeys

The enhancement of the vestibulo-ocular reflex (VOR) gain in the eccentric rotation is mediated by the otolith organs. Functional recovery of the otolith-ocular reflex after deafferentation of the otolith organs was examined in squirrel monkeys, using the enhancement of the eccentric VOR gain as an indicator of the reflex. After unilateral deafferentation of the otolith organs, the enhancement of the eccentric VOR gain decreased and then recovered completely within eight weeks. However, the eccentric VOR gain was not enhanced after contralateral side lesions. These findings demonstrate that functional recovery of the otolith-ocular reflex is achieved after unilateral deafferentation of the otolith organs, and that afferents from the remaining otolith organs are necessary for the functional compensation.

Sodium concentration in saliva along the time course of experimental Coriolis sickness

Procedures designed to evaluate the severity of motion sickness have included subjective reporting of changes in salivation. In order to increase objectivity, we studied the sodium concentration of saliva, which is directly related to the flow rate. Healthy adults with normal vestibular function underwent a modified Coriolis Sickness Susceptibility Index (CSSI) test, utilizing a staircase profile. Saliva was collected without interrupting the stimulus by means of cotton placed beneath the subject's tongue for one minute. Samples were obtained 5 min prior to stimulation, 30 and 45 min following stimulus onset, and/or upon reaching the "nausea II" endpoint. Saliva for analysis by atomic absorption spectrophotometry was obtained by centrifugation of the cotton. A significant difference in sodium concentration was found between the baseline and 30-min sample (p less than 0.01). Although the amount of salivation was rather variable, the pattern of changes in sodium concentration was similar in all experimental cases.