Two-year carcinogenicity study of a novel plasticizer, bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate (Eco-DEHCH), by oral diet in Han Wistar rats.

Plasticizers are necessary for the usability of various products, including food contact materials. Exposure to plasticizers is most commonly made through the oral route. Several plasticizers have been reported to have adverse effects on humans and the environment. Thus, the present study aimed to determine the long-term toxicity and carcinogenicity of a novel plasticizer called bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate (Eco-DEHCH), which is an ecofriendly and biologically less harmful replacer. Groups of 50 male and 50 female Han Wistar rats were fed Eco-DEHCH at daily doses of 1,600, 5,000, or 16,000 ppm in their diet for at least 104 weeks. The rats were regularly monitored for mortality, clinical signs, body weight, food consumption, food efficiency, and perceivable mass. All animals were subjected to complete necropsy and histopathological examination. The results indicate that the rats well tolerated chronic exposure to Eco-DEHCH at highest daily doses of 16,000 ppm, with was equivalent to 805.1 mg/kg/day in males and 1060.6 mg/kg/day in females and did not show signs of toxicity or carcinogenicity. In conclusion, Eco-DEHCH could be a safe and promising alternative plasticizer.

Toxicology and safety study of L-tryptophan and its impurities for use in broiler feed.

L-tryptophan has been utilized as a feed additive in animal nutrition to improve growth performance, as well as a dietary supplement to alleviate various emotional symptoms in humans. Despite its benefits, concerns regarding its safety arose following the outbreak of eosinophilia-myalgia syndrome (EMS) among individuals who consumed L-tryptophan. The causative material of EMS was determined to be not L-tryptophan itself, but rather L-tryptophan impurities resulting from a specific manufacturing process. To investigate the effect of L-tryptophan and its impurities on humans who consume meat products derived from animals that were fed L-tryptophan and its impurities, an animal study involving broiler chickens was conducted. The animals in test groups were fed diet containing 0.065%-0.073% of L-tryptophan for 27 days. This study aimed to observe the occurrence of toxicological or EMS-related symptoms and analyze the residues of L-tryptophan impurities in meat products. The results indicated that there was no evidence of adverse effects associated with the test substance in the investigated parameters. Furthermore, most of the consumed EMS-causing L-tryptophan impurities did not remain in the meat of broiler chickens. Thus, this study demonstrated the safety of L-tryptophan and some of its impurities as a feed additive.

Toxicology and safety study of L-tryptophan and its impurities for use in swine.

L-tryptophan, an essential amino acid for physiological processes, metabolism, development, and growth of organisms, is widely utilized in animal nutrition and human health as a feed additive and nutritional supplement, respectively. Despite its known benefits, safety concerns have arisen due to an eosinophilia-myalgia syndrome (EMS) outbreak linked to L-tryptophan consumed by humans. Extensive research has established that the EMS outbreak was caused by an L-tryptophan product that contained certain impurities. Therefore, safety validations are imperative to endorse the use of L-tryptophan as a supplement or a feed additive. This study was conducted in tertiary hybrid [(Landrace × Yorkshire) × Duroc] pigs to assess general toxicity and potential risks for EMS-related symptoms associated with L-tryptophan used as a feed additive. Our investigation elucidated the relationship between L-tryptophan and EMS in swine. No mortalities or clinical signs were observed in any animals during the administration period, and the test substance did not induce toxic effects. Hematological analysis and histopathological examination revealed no changes in EMS-related parameters, such as eosinophil counts, lung lesions, skin lesions, or muscle atrophy. Furthermore, no test substance-related changes occurred in other general toxicological parameters. Through analyzing the tissues and organs of swine, most of the L-tryptophan impurities that may cause EMS were not retained. Based on these findings, we concluded that incorporating L-tryptophan and its impurities into the diet does not induce EMS in swine. Consequently, L-tryptophan may be used as a feed additive throughout all growth stages of swine without safety concerns.

Combination of PD-1 Checkpoint Blockade and Botulinum Toxin Type A1 Improves Antitumor Responses in Mouse Tumor Models of Melanoma and Colon Carcinoma.

BACKGROUND: Tumor innervation has been shown to be utilized by some solid cancers to support tumor initiation, growth, progression, and metastasis, as well as confer resistance to immune checkpoint blockade through suppression of antitumor immunologic responses. Since botulinum neurotoxin type A1 (BoNT/A1) blocks neuronal cholinergic signaling, its potential use as an anticancer drug in combination with anti-PD-1 therapy was investigated in four different syngeneic mouse tumor models. METHODS: Mice implanted with breast (4T1), lung (LLC1), colon (MC38), and melanoma (B16-F10) tumors were administered a single intratumoral injection of 15 U/kg BoNT/A1, repeated intraperitoneal injections of 5 mg/kg anti-PD-1 (RMP1-14), or both. RESULTS: Compared to the single-agent treatments, anti-PD-1 and BoNT/A1 combination treatment elicited significant reduction in tumor growth among B16-F10 and MC38 tumor-bearing mice. The combination treatment also lowered serum exosome levels in these mice compared to the placebo control group. In the B16-F10 syngeneic mouse tumor model, anti-PD-1 + BoNT/A1 combination treatment lowered the proportion of MDSCs, negated the increased proportion of Treg cells, and elicited a higher number of tumor-infiltrating CD4+ and CD8+ T lymphocytes into the tumor microenvironment compared to anti-PD-1 treatment alone. CONCLUSION: Our findings demonstrate the synergistic antitumor effects of BoNT/A1 and PD-1 checkpoint blockade in mouse tumor models of melanoma and colon carcinoma. These findings provide some evidence on the potential application of BoNT/A1 as an anticancer drug in combination with immune checkpoint blockade and should be further explored.

Carcinogenicity assessment of tegoprazan in Sprague-Dawley (Crl:CD) rats and ICR (Crl:CD1) mice.

Tegoprazan is a novel potassium-competitive acid blocker (P-CAB) that reversibly inhibits the proton pump in gastric parietal cells and has been approved for the treatment of acid-related diseases in Korea. This study aimed to evaluate the carcinogenic potential of tegoprazan in Sprague-Dawley rats and CD-1 mice. Tegoprazan was administered daily by oral gavage to rats for up to 94 weeks and mice for up to 104 weeks. Evidence of carcinogenic potential of tegoprazan was identified in rats only and was limited to benign and/or malignant neuroendocrine cell tumors at exposures >7-fold of the recommended human dose. Glandular stomach findings were considered secondary to the expected pharmacology of tegoprazan, characterized by their location in the fundic and body regions of the stomach. Overall, tegoprazan induced gastric enterochromaffin-like (ECL) cell tumors in SD rats, but did not produce any treatment-related statistically significant increase in the incidence of neoplasms relevant to humans when administered to SD rats and CD-1 mice by gavage at doses up to 300 and 150 mg/kg/day, respectively. Gastric ECL cell tumors are thought to be induced by the exaggerated indirect pharmacological effect of tegoprazan, similar to that reported for proton pump inhibitors (PPIs) and other P-CABs.

Association between ARID2 and RAS-MAPK pathway in intellectual disability and short stature.

BACKGROUND: ARID2 belongs to the Switch/sucrose non-fermenting complex, in which the genetic defects have been found in patients with dysmorphism, short stature and intellectual disability (ID). As the phenotypes of patients with ARID2 mutations partially overlap with those of RASopathy, this study evaluated the biochemical association between ARID2 and RAS-MAPK pathway. METHODS: The phenotypes of 22 patients with either an ARID2 heterozygous mutation or haploinsufficiency were reviewed. Comprehensive molecular analyses were performed using somatic and induced pluripotent stem cells (iPSCs) of a patient with ARID2 haploinsufficiency as well as using the mouse model of Arid2 haploinsufficiency by CRISPR/Cas9 gene editing. RESULTS: The phenotypic characteristics of ARID2 deficiency include RASopathy, Coffin-Lowy syndrome or Coffin-Siris syndrome or undefined syndromic ID. Transient ARID2 knockout HeLa cells using an shRNA increased ERK1 and ERK2 phosphorylation. Impaired neuronal differentiation with enhanced RAS-MAPK activity was observed in patient-iPSCs. In addition, Arid2 haploinsufficient mice exhibited reduced body size and learning/memory deficit. ARID2 haploinsufficiency was associated with reduced IFITM1 expression, which interacts with caveolin-1 (CAV-1) and inhibits ERK activation. DISCUSSION: ARID2 haploinsufficiency is associated with enhanced RAS-MAPK activity, leading to reduced IFITM1 and CAV-1 expression, thereby increasing ERK activity. This altered interaction might lead to abnormal neuronal development and a short stature.

Toxicological profile of bisphenol F via comprehensive and extensive toxicity evaluations following dermal exposure.

Bisphenol F (BPF) is classified as a harmful substance by the U.S. Environmental Protection Agency. Although previous studies focused on human exposure to BPF via direct consumption or inhalation, few investigators assessed potential toxicological effects following skin contact. The aim of this study was to examine (1) the degree and pattern by which BPF is absorbed onto the skin in vivo, and (2) determination of toxicity and safety using the following tests: acute dermal; a 28-day repeat dermal; a skin irritation; an eye irritation; and a skin sensitization. As indicated by the amount of BPF remaining in the epidermis or dermis, data demonstrated that BPF was absorbed through the skin at a 26.5% rate. BPF penetrated the subcutaneous layer at a "fast rate" (Kp: 2.2E-02). Although no toxicological changes or local irritation were observed following skin exposure, BPF induced potent sensitization. In summary, the findings of this study showed that BPF penetrated and was absorbed into the skin at a high rate which was associated with enhanced chemical-induced skin sensitization and this may have significant implications following exposure of skin to BPF.

Histopathologic findings of vascular damage after mechanical thrombectomy using stent retriever in canine models.

Although mechanical thrombectomy is a powerful predictor of stroke outcome, it induces vessel wall injury in the acute phase. This study aimed to analyze the degree and the condition of recovery of wall injury after the acute phase via angiography and histopathological analysis of autopsied canine models. Digital subtraction angiography (DSA) and embolization with autologous thrombus were performed in six canines. The model of arterial occlusion was effective in all target vessels. Mechanical thrombectomy was performed in completely occluded vessels using stent retriever. Follow-up angiographic and histopathologic evaluations were performed 1 month later. Complete recanalization using stent retriever was achieved in four cases. Slight residual vessel narrowing after recanalization and moderate narrowing was observed in one case each. Histopathological analysis showed that inflammation, hemorrhage, and device-induced medial injury were not observed in any of the cases. Severe intimal proliferation (grade 4), marked diffuse thrombosis (grade 4), and weak vascular endothelial cell loss (grade 1) were observed in one case and weak endovascular proliferation was observed in one case. Although successful complete recanalization was achieved with a single mechanical thrombectomy attempt and no change was observed in the follow-up DSA, special attention should be paid to postoperative follow-up, as device-induced intimal proliferation, diffuse thrombosis, and endothelial cell loss may remain after 1 month.

C1q/TNF-α-Related Protein 1 (CTRP1) Maintains Blood Pressure Under Dehydration Conditions.

RATIONALE: Circulating CTRP1 (C1q/TNF-α [tumor necrosis factor-α]-related protein 1) levels are increased in hypertensive patients compared with those in healthy subjects. Nonetheless, little is known about the molecular and physiological function of CTRP1 in blood pressure (BP) regulation. OBJECTIVE: To investigate the physiological/pathophysiological role of CTRP1 in BP regulation. METHODS AND RESULTS: CTRP1 production was increased to maintain normotension under dehydration conditions, and this function was impaired in inducible CTRP1 KO (knockout) mice (CTRP1 ΔCAG). The increase in CTRP1 under dehydration conditions was mediated by glucocorticoids, and the antagonist mifepristone prevented the increase in CTRP1 and attenuated BP recovery. Treatment with a synthetic glucocorticoid increased the transcription, translation, and secretion of CTRP1 from skeletal muscle cells. Functionally, CTRP1 increases BP through the stimulation of the AT1R (Ang II [angiotensin II] receptor 1)-Rho (Ras homolog gene family)/ROCK (Rho kinase)-signaling pathway to induce vasoconstriction. CTRP1 promoted AT1R plasma membrane trafficking through phosphorylation of AKT and AKT substrate of 160 kDa (AS160). In addition, the administration of an AT1R blocker, losartan, recovered the hypertensive phenotype of CTRP1 TG (transgenic) mice. CONCLUSIONS: For the first time, we provide evidence that CTRP1 contributes to the regulation of BP homeostasis by preventing dehydration-induced hypotension.

Metformin Alleviates Left Ventricular Diastolic Dysfunction in a Rat Myocardial Ischemia Reperfusion Injury Model.

An increased incidence of myocardial infarction (MI) has recently emerged as the cause of cardiovascular morbidity and mortality worldwide. In this study, cardiac function was investigated in a rat myocardial ischemia/reperfusion (I/R) model using echocardiography. Metformin administration significantly increased ejection fraction and fractional shortening values on Days 3 and 7 when MI occurred, indicating that metformin improved left ventricular systolic function. In the Sham + MET and MI + MET groups, the E' value was significantly different up to Day 3 but not at Day 7. This may mean that left ventricular diastolic function was effectively restored to some extent by Day 7 when metformin was administered. These results suggest that diastolic dysfunction, assessed by echocardiography, does not recover in the early phase of ischemic reperfusion injury in the rat myocardial I/R model. However, administering metformin resulted in recovery in the early phase of ischemic reperfusion injury in this model. Further gene expression profiling of left ventricle tissues revealed that the metformin-treated group had notably attenuated immune and inflammatory profiles. To sum up, a rat myocardial I/R injury model and ultrasound-based assessment of left ventricular systolic and diastolic function can be used in translational research and for the development of new heart failure-related drugs, in addition to evaluating the potential of metformin to improve left ventricular (LV) diastolic function.

Identifying Stabilin-1 and Stabilin-2 Double Knockouts in Reproduction and Placentation: A Descriptive Study.

The placenta undergoes reconstruction at different times during fetal development to supply oxygen and nutrients required throughout pregnancy. To accommodate the rapid growth of the fetus, small spiral arteries undergo remodeling in the placenta. This remodeling includes apoptosis of endothelial cells that line spiral arteries, which are replaced by trophoblasts of fetal origin. Removal of dead cells is critical during this process. Stabilin-1 (Stab1) and stabilin-2 (Stab2) are important receptors expressed on scavenger cells that absorb and degrade apoptotic cells, and Stab1 is expressed in specific cells of the placenta. However, the role of Stab1 and Stab2 in placental development and maintenance remain unclear. In this study, we assessed Stab1 and Stab2 expression in the placenta and examined the reproductive capacity and placental development using a double-knockout mouse strain lacking both Stab1 and Stab2 (Stab1/2 dKO mice). Most pregnant Stab1/2 dKO female mice did not produce offspring and exhibited placental defects, including decidual hemorrhage and necrosis. Findings of this study offer the first description of the phenotypic characteristics of placentas and embryos of Stab1/2 dKO females during pregnancy, suggesting that Stab1 and Stab2 are involved in placental development and maintenance.

Sappanone A Prevents Left Ventricular Dysfunction in a Rat Myocardial Ischemia Reperfusion Injury Model.

The incidence of myocardial infarction, among the causes of cardiovascular morbidity and mortality, is increasing globally. In this study, left ventricular (LV) dysfunction, including LV systolic and diastolic function, was investigated in a rat myocardial ischemia/reperfusion injury model with echocardiography. The homoisoflavanone sappanone A is known for its anti-inflammatory effects. Using echocardiography, we found that sappanone A administration significantly improved LV systolic and diastolic function in a rat myocardial ischemia/reperfusion injury model, especially in the early phase development of myocardial infarction. Based on myocardial infarct size, serum cardiac marker assay, and histopathological evaluation, sappanone A showed higher efficacy at the doses used in our experiments than curcumin and was evaluated for its potential to improve LV function.

Use of 3D Human Liver Organoids to Predict Drug-Induced Phospholipidosis.

Drug-induced phospholipidosis (PL) is a storage disorder caused by the formation of phospholipid-drug complexes in lysosomes. Because of the diversity of PL between species, human cell-based assays have been used to predict drug-induced PL in humans. We established three-dimensional (3D) human liver organoids as described previously and investigated their liver characteristics through multiple analyses. Drug-induced PL was initiated in these organoids and in monolayer HepG2 cultures, and cellular changes were systemically examined. Organoids that underwent differentiation showed characteristics of hepatocytes rather than HepG2 cells. The organoids also survived under PL-inducing drug conditions for 48 h and maintained a more stable albumin secretion level than the HepG2 cells. More cytoplasmic vacuoles were observed in organoids and HepG2 cells treated with more potent PL-induced drugs, but to a greater extent in organoids than in HepG2 cells. Lysosome-associated membrane protein 2, a marker of lysosome membranes, showed a stronger immunohistochemical signal in the organoids. PL-distinctive lamellar bodies were observed only in amiodarone-treated organoids by transmission electron microscopy. Human liver organoids are thus more sensitive to drug-induced PL and less affected by cytotoxicity than HepG2 cells. Since PL is a chronic condition, these results indicate that organoids better reflect metabolite-mediated hepatotoxicity in vivo and could be a valuable system for evaluating the phospholipidogenic effects of different compounds during drug development.

Subretinal transplantation of human embryonic stem cell-derived retinal pigment epithelium (MA09-hRPE): A safety and tolerability evaluation in minipigs.

This study aimed to determine the safety and tolerability of the subretinal injection of hESC-derived RPE cells at higher doses than the established clinical dose (5 × 104 cells/150 µL) by using minipigs. The hESC-derived RPE cells (60 or 120 × 104 cells/150 µL) were injected in subretinal region, and minipigs were sacrificed at Weeks 4, 8, and 12 post-surgery. Time-course examination was performed by using fundus photography, optical coherence tomography (OCT), histopathology, and fluorescence in situ hybridization (FISH). After surgery, retinal bleb and pigmentation were seen and retinal bleb became smaller gradually. In histopathology, cell clusters consisting of a uniform population of the round to oval cells were seen at the subretinal injection site. In immunohistochemistry, most of the cells were positive for anti-CD3 and CD45 antibodies but negative for anti-human nuclei antibody; transplanted cells were not detectable by DNA probe in FISH assay. Cell clusters were thought to be a host immune response to trauma or transplanted cells. There were no other changes related to subretinal RPE cell injection. These results suggested that subretinal injection of hESC-derived RPE cells (60 and 120 × 104 cells/150 µL) in minipigs is well-tolerated and safe.

Sirolimus-eluting Biodegradable Poly-l-Lactic Acid Stent to Suppress Granulation Tissue Formation in the Rat Urethra.

Purpose To investigate the use of sirolimus-eluting biodegradable stents (SEBSs) to suppress granulation tissue formation after stent placement in a rat urethral model. Materials and Methods All experiments were approved by the animal research committee. A total of 36 male Sprague-Dawley rats were randomized into three equal groups after biodegradable stent placement. Group A received control biodegradable stents. Groups B and C received stents coated with 90 µg/cm2 and 450 µg/cm2 sirolimus, respectively. Six rats in each group were sacrificed after 4 weeks; the remaining rats were sacrificed after 12 weeks. The therapeutic effectiveness of SEBSs was assessed by comparing the results of retrograde urethrography and histologic examination. Analysis of variance with post hoc comparisons was used to evaluate statistical differences. Results SEBS placement was technically successful in all rats. Urethrographic and histologic examinations revealed significantly less granulation tissue formation at both time points in the rats receiving SEBSs (groups B and C) compared with those that received control stents (group A) (P < .05 for all). There were no significant differences in urethrographic and histologic findings between groups B and C (P > .05 for all). However, the mean number of epithelial layers in group B was higher than that in group C at 4 weeks after stent placement (P < .001). Apoptosis increased in group C compared with groups A and B (P < .05 for all). Conclusion The use of SEBSs suppressed granulation tissue formation secondary to stent placement in a rat urethral model; local therapy with SEBSs may be used to decrease stent-related granulation tissue formation. © RSNA, 2017.

Biocompatibility and Efficiency of Biodegradable Magnesium-Based Plates and Screws in the Facial Fracture Model of Beagles.

PURPOSE: A biodegradable magnesium alloy system has been developed as a substitute for conventional plates and screws made of titanium or absorbable polymer. However, previous studies were limited to small animal experiments using screws or wires. In the present study, we preliminarily evaluated the biocompatibility and effectiveness of human standard-size biodegradable magnesium-based plates and screws in facial fractures of beagles. MATERIALS AND METHODS: Fracture lines were created bilaterally in the zygomatic arches of 6 beagles. They were fixed in situ with plates and screws made of magnesium alloy mixed with calcium and zinc (experimental group) or absorbable polymer (control group). Laboratory testing, radiologic imaging, histologic analysis, and mechanical testing were performed 4 weeks postoperatively. RESULTS: Inflammatory reactions were not significantly increased in any animal. Mechanical testing showed greater ultimate load and structural stiffness in the experimental group. In the histologic analysis, the void area and bone regeneration area were increased in the experimental, and the implant area and soft tissue area were increased in the control group. Radiologically, 3-dimensional micro-computed tomography showed no differences in the bone gap area between the 2 groups. A temporary increase in hydrogen gas around the magnesium implants regressed spontaneously and did not affect bone healing significantly. CONCLUSIONS: Magnesium-based biodegradable plates and screws showed good biocompatibility and offered considerable stability for fixating facial bone fractures in the early bone-healing process. These results show the possibilities for the future development of magnesium alloy plates and screws for craniomaxillofacial fixation in humans.

Evaluation of Circulating MicroRNA Biomarkers in the Acute Pancreatic Injury Dog Model.

This study aimed to evaluate the usefulness of four microRNAs (miRNAs) in an acute pancreatic injury dog model. Acute pancreatitis was induced by infusion of cerulein for 2 h (7.5 µg/kg/h). The levels of well-known miRNAs, microRNA-216a (miR-216a) and microRNA-375 (miR-375), and new candidates microRNA-551b (miR-551b), and microRNA-7 (miR-7), were measured at 0, 0.5, 1, 2, 6, 12, and 24 h with serum amylase and lipase, and histopathological examination was performed. Among the four miRNAs, miR-216a and miR-375, and serum enzymes were significantly increased by cerulein treatment. The expression levels of miRNAs and serum enzymes peaked at 2⁻6 h with a similar pattern; however, the overall increases in miR-216a and miR-375 levels were much higher than those of the serum enzyme biomarkers. Increased levels of miR-216a and miR-375 were most highly correlated to the degree of individual histopathological injuries of the pancreas, and showed much greater dynamic response than serum enzyme biomarkers. Twenty-four-hour time-course analysis in this study revealed time-dependent changes of miRNA expression levels, from initial increase to decrease by predose level in acute pancreatitis. Our findings demonstrate that, in dogs, miR-216a and miR-375 have the potential to sensitively detect pancreatitis and reflect well the degree of pancreatic injury, whereas miR-551b and miR-7 do not.

Development of a Mouse Model of Prostate Cancer Using the Sleeping Beauty Transposon and Electroporation.

The Sleeping Beauty (SB) transposon system is non-viral and uses insertional mutagenesis, resulting in the permanent expression of transferred genes. Although the SB transposon is a useful method for establishing a mouse tumor model, there has been difficulty in using this method to generate tumors in the prostate. In the present study, electroporation was used to enhance the transfection efficiency of the SB transposon. To generate tumors, three constructs (a c-Myc expression cassette, a HRAS (HRas proto-oncogene, GTPase) expression cassette and a shRNA against p53) contained within the SB transposon plasmids were directly injected into the prostate. Electroporation was conducted on the injection site after the injection of the DNA plasmid. Following the tumorigenesis, the tumors were monitored by animal PET imaging and identified by gross observation. After this, the tumors were characterized by using histological and immunohistochemical techniques. The expression of the targeted genes was analyzed by Real-Time qRT-PCR. All mice subjected to the injection were found to have prostate tumors, which was supported by PSA immunohistochemistry. To our knowledge, this is the first demonstration of tumor induction in the mouse prostate using the electroporation-enhanced SB transposon system in combination with c-Myc, HRAS and p53. This model serves as a valuable resource for the future development of SB-induced mouse models of cancer.

Intravoxel incoherent motion MRI for monitoring the therapeutic response of hepatocellular carcinoma to sorafenib treatment in mouse xenograft tumor models.

Background With the introduction of targeted therapies, there has been a growing need for non-invasive imaging methods which accurately evaluate therapeutic effects and overcome the limitations of tumor size-based therapeutic response assessments. Purpose To assess diagnostic values of intra-voxel incoherent motion (IVIM) imaging in evaluating therapeutic effects of sorafenib on hepatocellular carcinoma (HCC) using mouse xenograft model. Material and Methods Twenty-four mice bearing Huh-7 were divided into a control group and two treatment groups received sorafenib doses of 5 mg/kg (5 mg-Tx) or 30 mg/kg (30 mg-Tx). IVIM imaging was performed using 10 b-values (0-900 s/mm2). The apparent diffusion coefficient (ADC), diffusion coefficient ( D), and perfusion fraction ( f) were measured for whole tumors and tumor periphery. Changes between baseline and post-treatment parameters ( Δ ADC, Δ D, and Δ f) were calculated, and these parameters were compared with microvessel density (MVD) and area of tumor cell death. Results The post-treatment f and Δ f for tumor periphery were significantly higher in control group, followed by 5 mg-Tx and 30 mg-Tx ( P < 0.001). MVD showed significant positive correlation with post-treatment f ( r = 0.584, P = 0.003) and negative correlation with D ( r = -0.495, P = 0.014) for tumor periphery, while no parameter showed significant correlation with area of tumor cell death. Conclusion The f is significantly correlated with MVD of HCC, and could potentially be used to evaluate the anti-angiogenic effects of sorafenib.

Difference in the intratumoral distributions of extracellular-fluid and intravascular MR contrast agents in glioblastoma growth.

Contrast enhancement by an extracellular-fluid contrast agent (CA) (Gd-DOTA) depends primarily on the blood-brain-barrier permeability (bp), and transverse-relaxation change caused by intravascular T2 CA (superparamagnetic iron oxide nanoparticles, SPIONs) is closely associated with the blood volume (BV). Pharmacokinetic (PK) vascular characterization based on single-CA-using dynamic contrast-enhanced MRI (DCE-MRI) has shown significant measurement variation according to the molecular size of the CA. Based on this recognition, this study used a dual injection of Gd-DOTA and SPIONs for tracing the changes of bp and BV in C6 glioma growth (Days 1 and 7 after the tumor volume reached 2 mL). bp was quantified according to the non-PK parameters of Gd-DOTA-using DCE-MRI (wash-in rate, maximum enhancement ratio and initial area under the enhancement curve (IAUC)). BV was estimated by SPION-induced ΔR2 * and ΔR2 . With validated measurement reliability of all the parameters (coefficients of variation ≤10%), dual-contrast MRI demonstrated a different region-oriented distribution between Gd-DOTA and SPIONs within a tumor as follows: (a) the BV increased stepwise from the tumor center to the periphery; (b) the tumor periphery maintained the augmented BV to support continuous tumor expansion from Day 1 to Day 7; (c) the internal tumor area underwent significant vascular shrinkage (i.e. decreased ΔR2 and ΔR2 ) as the tumor increased in size; (d) the tumor center showed greater bp-indicating parameters, i.e. wash-in rate, maximum enhancement ratio and IAUC, than the periphery on both Days 1 and 7 and (e) the tumor center showed a greater increase of bp than the tumor periphery in tumor growth, as suggested to support tumor viability when there is insufficient blood supply. In the MRI-histologic correlation, a prominent BV increase in the tumor periphery seen in MRI was verified with increased fluorescein isothiocyanate-dextran signals and up-regulated immunoreactivity of CD31-VEGFR. In conclusion, the spatiotemporal alterations of BV and bp in glioblastoma growth, i.e. augmented BV in the tumor periphery and increased bp in the center, can be sufficiently evaluated by MRI with dual injection of extracellular-fluid Gd chelates and intravascular SPION.