The Role of microRNAs Related to Apoptosis for N-Methyl-d-Aspartic Acid-Induced Neuronal Cell Death in the Murine Retina.

Glaucoma is one of the leading causes of acquired blindness and characterized by retinal ganglion cell (RGC) death. MicroRNAs are small noncoding RNAs that degrade their target mRNAs. Apoptosis is one of the common mechanisms leading to neuronal death in many neurodegenerative diseases, including glaucoma. In the present study, we identified microRNAs that modulate RGC death caused by the intravitreal injection of N-methyl-d-aspartic acid (NMDA). We found an upregulation of miR-29b and downregulation of miR-124 in the retina of the NMDA-injected eyes. The intravitreal injection of an miR-29b inhibitor 18 h before NMDA injection reduced RGC death and the downregulation of myeloid cell leukemia 1 (MCL-1), an anti-apoptotic factor, induced by intravitreal NMDA. The intravitreal injection of an miR-124 mimic 18 h before NMDA injection also reduced RGC death and the upregulation of B-cell/chronic lymphocytic leukemia lymphoma 2 (bcl-2)-associated X protein (Bax) and bcl-2 interacting protein (Bim), pro-apoptotic factors, induced by intravitreal NMDA. These data suggest that expressional changes in microRNA are involved in the excitotoxicity of RGCs, and that complement and/or inhibition of microRNA may be a potential therapeutic approach for the diseases related to the excitotoxicity of RGCs, such as glaucoma and retinal central artery occlusion.

The process of methylglyoxal-induced retinal capillary endothelial cell degeneration in rats.

Methylglyoxal, a highly reactive dicarbonyl compound, is increased and accumulated in patients with diabetic mellitus. Methylglyoxal forms advanced glycation end products (AGE), contributing to the pathogenesis of diabetic complications, including diabetic retinopathy. Recent studies have shown that methylglyoxal induces diabetic retinopathy-like abnormalities in retinal vasculature. In this study, we investigated the processes and mechanisms of methylglyoxal-induced retinal capillary endothelial cell degeneration in rats. Morphological changes in vascular components (endothelial cells, pericytes, and basement membranes) were assessed in the retinas 2, 7, and 14 days after intravitreal injection of methylglyoxal. Intravitreal methylglyoxal injection induced retinal capillary endothelial cell degeneration in a dose- and time-dependent manner. Changes in the shape and distribution of pericytes occurred before the initiation of capillary regression in the retinas of methylglyoxal-injected eyes. The receptor for AGEs (RAGEs) antagonist FPS-ZM1, and the matrix metalloproteinase (MMP) inhibitor GM6001 significantly attenuated methylglyoxal-induced capillary endothelial cell degeneration. FPS-ZM1 failed to prevent pathological changes in pericytes in methylglyoxal-injected eyes. In situ zymography revealed that MMP activity was enhanced at sites of blood vessels with reduced pericyte coverage in methylglyoxal-injected eyes. These results suggest that intravitreal methylglyoxal injection induces pathological changes in pericytes before the initiation of capillary endothelial cell degeneration via an AGE-RAGE-independent pathway. The capillary endothelial cell degeneration is mediated by activating the AGE-RAGE pathway and increasing MMP activity in endothelial cells by impairing pericyte function in the retina.

Development of a novel purification method for AAV vectors using tangential flow filtration.

Adeno-associated virus (AAV) vector can efficiently transduce therapeutic genes in various tissue types with less side effects; however, owing to complex multistep processes during manufacture, there have been surges in the pricing of recently approved AAV vector-based gene therapy products. This study aimed to develop a simple and efficient method for high-quality purification of AAV vector via tangential flow filtration (TFF), which is commonly used for concentration and diafiltration of solutions during AAV vector purification. We established a novel purification method using TFF and surfactants. Treatment with two classes of surfactants (anionic and zwitterionic) successfully inhibited the aggregation of residual proteins separated from the AAV vector in the crude product by TFF, obtaining a clearance of 99.5% residual proteins. Infectivity of the AAV vector purified using the new method was confirmed both in vitro and in vivo, and no remarkable inflammation or tissue damage was observed in mouse skeletal muscle after local administration. Overall, our proposed method could be used to establish a platform for the purification of AAV vector.

Validation of the obesity paradox by body mass index and waist circumference in patients undergoing percutaneous coronary intervention.

BACKGROUND: The paradoxical association of obesity with mortality, named the "obesity paradox", has been inconsistent, possibly due to a difference between body mass index (BMI) and central obesity, estimated by waist circumference (WC) as patterns of adiposity. SUBJECTS/METHODS: We enrolled 8513 participants from the Kumamoto Intervention Conference Study, a multicenter registry that included consecutive patients undergoing percutaneous coronary intervention (PCI) at 18 centers between 2008 and 2017 in Japan. Patients were divided into quartiles in ascending order of the BMI or WC. The primary endpoints were all-cause mortality and cardiovascular death within a year. RESULTS: There were 186 deaths (case fatality rate, 22.1/1000 person-years) during the follow-up period. The lowest group (1st quartile) of BMI or WC had the worst prognosis among the quartiles (1st quartile, 4.2%; 2nd quartile, 1.9%; 3rd quartile, 1.5%; 4th quartile, 1.1%; P < 0.001 (χ2) and 1st quartile, 4.1%; 2nd quartile, 2.3%; 3rd quartile, 1.2%; 4th quartile, 1.5%; P < 0.001 (χ2), respectively). Similar results were obtained for cardiovascular death. In a multivariable analysis adjusted by nine conventional factors, the lowest group (1st quartile) of BMI (hazards ratio, 2.748; 95% confidence interval [CI], 1.712-4.411) and WC (hazards ratio, 2.340; 95% CI, 1.525-3.589) were independent prognostic factors for all-cause mortality. By dividing the participants into two groups according to either the BMI or WC based on the National Cholesterol Education Program Adult Treatment Panel III and World Health Organization classification, the highest mortality was observed in the lower group. However, the C-statistic after adding BMI (quartile) to conventional factors was found to be slightly higher than BMI (two categories) and WC (two categories) (0.735 vs. 0.734). CONCLUSIONS: The obesity paradox was observed in patients after PCI, and single-use of BMI (or WC) was sufficient to predict the prognosis of patients after PCI.

Pharmacological inhibition of Na+/K+-ATPase induces neurovascular degeneration and glial cell alteration in the rat retina.

Na+/K+-ATPase (NKA) plays an important role in ion homeostasis and neurotransmitter uptake. In the retina, multidirectional communications among neurons, glia, and blood vessels (that is, neuro-glio-vascular interaction) are crucial for maintaining tissue homeostasis. We investigated the role of NKA in the elements of neuro-glio-vascular unit in neonatal and adult rat retinas. Male Sprague-Dawley rats (1- and 8-week-old) were injected intravitreally with ouabain (20 nmol/eye), an inhibitor of NKA. Morphological changes in retinal neurons, glia, and blood vessels were examined. The intravitreal injection of ouabain decreased the number of cells in the ganglion cell layer, as well as the thicknesses of the inner plexiform and inner nuclear layers in neonatal and adult rats compared to age-matched controls. The ouabain-induced neuronal cell damage was partially prevented by D-(-)-2-amino-5-phosphonopentanoic acid, an antagonist of N-methyl-D-aspartic acid receptors. In the deep retinal vascular plexus of the ouabain-injected eyes, angiogenesis was delayed in neonatal rats, whereas capillary degeneration occurred in adult rats. The immunoreactivity of glutamine synthetase and vascular endothelial growth factor (VEGF) decreased in the retinas of neonatal and adult rats injected intravitreally with ouabain. The immunoreactivity of glial fibrillary acidic protein was enhanced in the retinas of ouabain-injected adult eyes. After the ouabain injection, CD45-positive leukocytes and Iba1-positive microglia increased in the inner retinal layer of neonatal rats, whereas they increased in the middle retinal layer of adult rats. These results suggest that the inhibition of NKA induces the degeneration of neuronal and vascular cells and alteration of glial cells in both neonatal and adult retinas. In addition to the direct effects of NKA inhibition, the disturbance of retinal glutamate metabolism and decreased VEGF expression may contribute to neurovascular degeneration. The activity of NKA is crucial for maintaining elements of neuro-glio-vascular unit in the retina.

East Asian variant aldehyde dehydrogenase type 2 genotype exacerbates ischemia/reperfusion injury with ST-elevation myocardial infarction in men: possible sex differences.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) detoxifies toxic aldehydes generated during ischemia/reperfusion (I/R) injury in ST-elevation myocardial infarction (STEMI). The deficient variant ALDH2 genotype (ALDH2*2) is prevalent among East Asians. Whether ALDH2*2 exacerbates I/R injury of in patients with STEMI is not known. The study subjects comprised 218 Japanese patients with STEMI (158 men and 60 women, mean age 67.9 ± 11.9) who underwent successful percutaneous coronary intervention. Of these, 120 (55.0%) were the carriers of variant ALDH2*2 and 98 (45.0%) those of wild ALDH2*1/*1 on genotyping. There were no differences in clinical characteristics between the ALDH2*2 and ALDH2*1/*1 group except lower alcohol habit (14.2% vs 46.3%, P < 0.001) in the ALDH2*2 group. The peak plasma levels of creatine phosphokinase myocardial binding (CKMB), a marker of myocardial injury, however, were significantly higher in the patients with ALDH2*2 than in those with ALDH2*1/*1 [a median 275.0 (175.8-407.5) vs 177.5 (126.9-344.3) U/L, P = 0.001] among men but not among women (P = 0.811). There was a significant interaction between men (male sex) and ALDH2*2 for I/R injury (χ2 = 4.425, P = 0.040). The variant ALDH2*2 was associated with more severe I/R injury than the wild ALDH2*1/*1 in STEMI patients in men with possible sex differences.

Impact of cerebrovascular comorbidity on prognosis in Japanese patients undergoing PCI: 1-year data from Japanese multicenter registry (KICS).

Cardiovascular and cerebrovascular diseases are considered the principal cause of morbidity and mortality worldwide; the effect of stroke-induced cardiac manifestations is well recognized; however, not enough clinical data have been found about the impact of stroke with underlying cardiac disease. This study's objective is to assess the impact of stroke on the prognosis of patients with underlying IHD, who underwent PCI treatment. This was a multicenter, 1-year observational study in patients undergoing PCI in one of the 17 participating centers across Japan. 18,495 patients were registered on the PCI list; 2481 patients had a prior stroke experience, whereas 15,979 were stroke-free. Our study revealed that stroke patients were significantly older (mean age 73.5 ± 9.6, 69.7(± 11.5), respectively), and suffered from more comorbidities (diabetes, hypertension, and chronic kidney disease, p < 0.0001). During the 1-year period, subjects with stroke showed higher incidence of clinical events compared to those without stroke; to illustrate, all-cause death accounted for 6.2% in patients with stroke, in contrast to only 2.8% in stroke-free patients (p < 0.0001), cardiac death amounted for 2.2 and 1.2%, respectively (p < 0.0001), recurrent stroke for 3.1% and 1.2% (p < 0.0001), non-cardiac death for 3.6 and 1.54% (p < 0.0001), and finally, hemorrhagic complications with 2.6 and 1.3% (p < 0.0001). Kaplan-Meier analysis revealed that stroke patients had a higher probability of all-cause mortality, cardiac death, and recurrent stroke (log-rank p < 0.0001). Cox hazard analysis also showed that the presence of stroke is a significant indicator in determining the outcome of cardiac death (HR = 1.457, 95% CI 1.036-2.051, p = 0.031); hence, proving it to be a crucial predictor on cardiac prognosis. History of prior stroke was common in PCI patients, and independently associated with a higher rate of subsequent cardiovascular and cerebrovascular events recurrence. Thus, highlighting an urgent need for comprehensive prevention of cardiac and cerebrovascular diseases.

Improved Prognostic Prediction by Combination of Early Initiation of Polymyxin B Hemoperfusion with Modified Gender-Age-Physiology Index in Acute Exacerbation of Idiopathic Pulmonary Fibrosis.

INTRODUCTION: Respiratory failure from acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is associated with high mortality. Direct hemoperfusion with polymyxin B-immobilized fiber column (PMX-DHP) has been reported to have beneficial effects on patients with AE-IPF. Whether patient characteristics influence the extent of this benefit remains unclear. METHODS: We retrospectively examined the records of 30 patients with AE-IPF who underwent PMX-DHP. The favorable factors of survival were determined using Cox proportional hazards analyses. RESULTS: The 1- and 12-month survival rates after PMX-DHP were 70.0% and 50.0%, respectively. The multivariate analysis revealed that low modified Gender-Age-Physiology (GAP) index (≤8 points) (hazard ratio [HR] 0.317, p = 0.015) and PMX-DHP received within 48 h of steroid pulse (HR 0.289, p = 0.012) were favorable factors. Notably, even in the patients with high modified GAP index (>8 points), that is, more advanced IPF, those who received PMX-DHP within 48 h of steroid pulse had a better prognosis than those who did after 48 h of the steroid pulse (p = 0.032). CONCLUSIONS: Early PMX-DHP initiation in patients with AE-IPF, specifically within 48 h after the steroid pulse therapy, may improve prognosis regardless of the severity of chronic phase of IPF before AE-IPF.

Pharmacological depletion of retinal neurons prevents vertical angiogenic sprouting without affecting the superficial vascular plexus.

BACKGROUND: In mice, a tri-layered (superficial, intermediate, and deep) vascular structure is formed in the retina during the third postnatal week. Short-term treatment of newborn mice with vascular endothelial growth factor (VEGF) receptor inhibitors delays the formation of superficial vascular plexus and this allows us to investigate the developmental process of superficial and deep vascular plexuses at the same time. Using this model, we examined the effect of pharmacological depletion of retinal neurons on the formation of superficial and deep vascular plexuses. RESULTS: Neuronal cell loss induced by an intravitreal injection of N-methyl-d-aspartic acid on postnatal day (P) 8 delayed vascular development in the deep layer but not in the superficial layer in mice treated with KRN633, a VEGF receptor inhibitor, on P0 and P1. In KRN633-treated mice, neuronal cell loss decreased the number of vertical sprouts originating from the superficial plexus without affecting the number of angiogenic sprouts growing in front. Neuronal cell loss did not impair networks of fibronectin and astrocytes in the superficial layer. CONCLUSIONS: Our results suggest that inner retinal neurons play a crucial role in forming the deep vascular plexus by directing the sprouts from the superficial blood vessels to the deep layer.

Clinical significance of reactive oxidative metabolites in patients with heart failure with reduced left ventricular ejection fraction.

BACKGROUND: We investigated the clinical significance of the derivative of reactive oxygen metabolites (DROM), a new marker of reactive oxygen species (ROS), in patients with heart failure (HF) with reduced left ventricular ejection fraction (LVEF) (HFrEF). METHODS AND RESULTS: Serum DROM concentrations were measured in 201 consecutive patients with HFrEF (EF < 50%) in stable condition. DROM values were significantly higher in patients with HFrEF than in risk-matched patients without HF (P < 0.01). They also correlated significantly with high-sensitivity C-reactive protein and B-type natriuretic peptide. Kaplan-Meier analysis demonstrated significantly higher probabilities of HF-related events in the high-DROM group than in the low-DROM group (log-rank test, P < 0.01). Multivariable Cox hazard analysis revealed that DROM were independent and significant predictors of cardiovascular events. In a subgroup analysis, DROM levels were also measured at the aortic root and coronary sinus in 49 patients. The transcardiac gradient of DROM values was significantly higher in patients with HFrEF than in patients without HF (P = 0.04), indicating an association between DROM production in the coronary circulation and HFrEF development. Changes in DROM following optimal therapy were significantly associated with LVEF improvement (r = 0.34, P = 0.04). CONCLUSIONS: The higher levels of DROM and their association with cardiovascular events suggest the clinical benefit of DROM measurements in the risk stratification of patients with HFrEF.

Coronary artery perforation into the upper gastrointestinal cavity due to gastric ulceration.

An 82-year-old man who had previously undergone a proximal gastrectomy with jejunal interposition surgery for stomach cancer was transferred to our hospital for massive hematemesis and hypotension. His electrocardiogram showed ST-segment elevation in lead ΙΙ, ΙΙΙ, aVF, which confirmed inferior myocardial infarction. Due to active hematemesis, upper endoscopy was performed initially. A visible vessel of gastric ulceration was discovered, and hemostasis was achieved using hemoclips. Subsequently, coronary angiography was performed since the right coronary artery (RCA) segment 4 atrioventricular (AV) was occluded. After thrombectomy and intravascular ultrasound (IVUS), 2.0 mm balloon angioplasty was done, and coronary perforation occurred. During coronary angiography, extravasation of the contrast material into the gastrointestinal cavity was noted. A covered stent was placed across segment 3 to segment 4 descending posteriorly (PD) to stop the blood supply to the perforation site of segment 4 AV. After stenting, adequate re-hemostasis was achieved. The patient was discharged after 28 days. This is the first report of a coronary artery perforation into the gastrointestinal cavity.

Impairment of endothelium-dependent vasodilator function of retinal blood vessels in adult rats with a history of retinopathy of prematurity.

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease, initiated by delayed retinal vascular growth after premature birth. In the majority of cases, ROP resolves spontaneously; however, a history of ROP may increase the risk of long-term visual problems. In this study, we evaluated the endothelial function of retinal blood vessels in adult rats with a history of ROP. ROP was induced in rats by subcutaneous injection of a vascular endothelial growth factor receptor tyrosine kinase inhibitor (KRN633) on postnatal day (P) 7 and P8. On P56, vasodilator responses to acetylcholine, GSK1016790A (an activator of transient receptor potential vanilloid 4 channels), NOR3 (a nitric oxide [NO] donor), and salbutamol (a ß2-adrenoceptor agonist) were assessed. Compared to age-matched controls, retinal vasodilator responses to acetylcholine and GSK1016790A were attenuated in P56 rats with a history of ROP. No attenuation of acetylcholine-induced retinal vasodilator response was observed under inhibition of NO synthase. Retinal vasodilator responses to NOR3 and salbutamol were unaffected. These results suggest that the production of and/or release of NO is impaired in retinal blood vessels in adult rats with a history of ROP. A history of ROP might increase the risk of impaired retinal circulation in adulthood.

Role of Epoxyeicosatrienoic Acids in Acetylcholine-Induced Dilation of Rat Retinal Arterioles in Vivo.

CYP epoxygenase-derived epoxyeicosatrienoic acids (EETs) contribute to endothelium-dependent hyperpolarization (EDH)-related dilation in multiple vascular beds. The present study aimed to determine the role of EETs in the acetylcholine (ACh)-induced dilation of retinal arterioles in rats in vivo. The vasodilator responses were assessed by determining the change in diameter of the retinal arterioles on images of the ocular fundus. The intravitreal injection of 17-octadecynoic acid (1.4 nmol/eye), an inhibitor of CYP epoxygenase, and 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EE-5(Z)-E; 2 nmol/eye), an antagonist of EETs, reduced the ACh (0.3-10 µg/kg/min)-induced dilation of the retinal arterioles. The EET antagonist attenuated the vasodilator response to ACh under blockade of nitric oxide (NO) synthases and cyclooxygenases with NG-nitro-L-arginine methyl ester (30 mg/kg) plus indomethacin (5 mg/kg). Intravitreal injection of 14,15-EET (0.5 nmol/eye) dilated retinal arterioles and the response was prevented by iberiotoxin, an inhibitor of large-conductance Ca2+-activated K+ (BKCa) channels (20 pmol/eye). These results suggest that ACh stimulates the production of EETs, thereby dilating the retinal arterioles via activation of BKCa channels. CYP epoxygenase-derived EETs may be involved in the EDH-related component of the ACh-induced dilation of the retinal arterioles.

Involvement of Gap Junctions in Acetylcholine-Induced Endothelium-Derived Hyperpolarization-Type Dilation of Retinal Arterioles in Rats.

An electrical communication between the endothelial and smooth muscle cells via gap junctions, which provides the signaling pathway known as endothelium-dependent hyperpolarization (EDH), plays a crucial role in controlling the vascular tone. In this study, we investigated the role of gap junctions in the acetylcholine (ACh)-induced EDH-type dilation of rat retinal arterioles in vivo. The dilator response was evaluated by measuring the diameter of retinal arterioles. Intravitreal injection of gap junction blockers (18ß-glycyrrhetinic acid and carbenoxolone) reduced the ACh-induced dilation of retinal arterioles. Moreover, the retinal arteriolar response to ACh was attenuated by 18ß-glycyrrhetinic acid under treatment with a combination of NG-nitro-L-arginine methyl ester (a nitric oxide (NO) synthase inhibitor; 30 mg/kg) and indomethacin (a cyclooxygenase inhibitor; 5 mg/kg). The NO- and prostaglandin-independent, EDH-related component of ACh-induced dilation of retinal arterioles was prevented by intravitreal injection of iberiotoxin, which inhibits large-conductance Ca2+-activated K+ channels. Furthermore, the combination of 18ß-glycyrrhetinic acid and iberiotoxin produced greater attenuation in the EDH-related response than that by the individual agent. Treatment with 18ß-glycyrrhetinic acid revealed no significant effect on NOR3 (an NO donor)-induced retinal vasodilator response. These results suggest that gap junctions contribute to the ACh-induced, EDH-type dilation of rat retinal arterioles in vivo.

Metformin Protects against NMDA-Induced Retinal Injury through the MEK/ERK Signaling Pathway in Rats.

Metformin, an anti-hyperglycemic drug of the biguanide class, exerts positive effects in several non-diabetes-related diseases. In this study, we aimed to examine the protective effects of metformin against N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinal damage in rats and determine the mechanisms of its protective effects. Male Sprague-Dawley rats (7 to 9 weeks old) were used in this study. Following intravitreal injection of NMDA (200 nmol/eye), the number of neuronal cells in the ganglion cell layer and parvalbumin-positive amacrine cells decreased, whereas the number of CD45-positive leukocytes and Iba1-positive microglia increased. Metformin attenuated these NMDA-induced responses. The neuroprotective effect of metformin was abolished by compound C, an inhibitor of AMP-activated protein kinase (AMPK). The AMPK activator, AICAR, exerted a neuroprotective effect in NMDA-induced retinal injury. The MEK1/2 inhibitor, U0126, reduced the neuroprotective effect of metformin. These results suggest that metformin protects against NMDA-induced retinal neurotoxicity through activation of the AMPK and MEK/extracellular signal-regulated kinase (ERK) signaling pathways. This neuroprotective effect could be partially attributable to the inhibitory effects on inflammatory responses.

The process of revascularization in the neonatal mouse retina following short-term blockade of vascular endothelial growth factor receptors.

Misdirected vascular growth frequently occurs in the neovascular diseases in the retina. However, the mechanisms are still not fully understood. In the present study, we created capillary-free zones in the central and peripheral retinas in neonatal mice by pharmacological blockade of vascular endothelial growth factor (VEGF) signaling. Using this model, we investigated the process and mechanisms of revascularization in the central and peripheral avascular areas. After the completion of a 2-day treatment with the VEGF receptor tyrosine kinase inhibitor KRN633 on postnatal day (P) 4 and P5, revascularization started on P8 in the central avascular area where capillaries had been dropped out. The expression levels of VEGF were higher in the peripheral than in the central avascular area. However, the expansion of the vasculature in the peripheral avascular retina remained suppressed until revascularization had been completed in the central avascular area. Additionally, we found disorganized endothelial cell division, misdirected blood vessels with irregular diameters, and abnormal fibronectin networks at the border of the vascular front and the avascular retina. In the central avascular area, a slight amount of fibronectin as non-vascular component re-formed to provide a scaffold for revascularization. Mechanistic analysis revealed that higher levels of VEGF attenuated the migratory response of endothelial cells without decreasing the proliferative activity. These results suggest that the presence of concentration range of VEGF, which enhances both migration and proliferation of the endothelial cells, and the structurally normal fibronectin network contribute to determine the proper direction of angiogenesis.

Changes in components of the neurovascular unit in the retina in a rat model of retinopathy of prematurity.

An impairment of cellular interactions between the elements of the neurovascular unit contributes to the onset and/or progression of retinal diseases. The present study aims to examine how elements of the neurovascular unit are altered in a rat model of retinopathy of prematurity (ROP). Neonatal rats were treated subcutaneously with the vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor KRN633 (10 mg/kg) on postnatal day (P) 7 and P8 to induce ROP. Morphological assessments were performed of blood vessels, astrocytes and neuronal cells in the retina. Aggressive angiogenesis, tortuous arteries and enlarged veins were observed in the retinal vasculature of KRN633-treated (ROP) rats from P14 to P28, compared to age-matched control (vehicle-treated) animals. Morphological abnormalities in the retinal vasculature showed a tendency toward spontaneous recovery from P28 to P35 in ROP rats. Immunofluorescence staining for glial fibrillary acidic protein and Pax2 (astrocyte markers) revealed that morphological changes to and a reduction in the number of astrocytes occurred in ROP rats. The developmental cell death was slightly accelerated in ROP rats; however, no visible changes in the morphology of retinal layers were observed on P35. The abnormalities in astrocytes might contribute, at least in part, to the formation of abnormal retinal blood vessels and the pathogenesis of ROP.

Myocardial extracellular volume quantification in cardiac CT: comparison of the effects of two different iterative reconstruction algorithms with MRI as a reference standard.

OBJECTIVES: To compare the effects of hybrid iterative reconstruction (HIR) and model-based iterative reconstruction (MBIR) that incorporates a beam-hardening model for myocardial extracellular volume (ECV) quantification by cardiac CT using MRI as a reference standard. METHODS: In this retrospective study, a total of 34 patients were evaluated using cardiac CT and MRI. Paired CT image sets were created using HIR and MBIR with a beam-hardening model. We calculated mean absolute differences and correlations between the global mid-ventricular ECV derived from CT and MRI via Pearson correlation analysis. In addition, we performed qualitative analysis of image noise and beam-hardening artifacts on postcontrast images using a four-point scale: 1 = extensive, 2 = strong, 3 = mild, and 4 = minimal. RESULTS: The mean absolute difference between the ECV derived from CT and MRI for MBIR was significantly smaller than that for HIR (MBIR 3.74 ± 3.59%; HIR 4.95 ± 3.48%, p = 0.034). MBIR improved the correlation between the ECV derived from CT and MRI when compared with HIR (MBIR, r = 0.60, p < 0.001; HIR, r = 0.47, p = 0.006). In qualitative analysis, MBIR significantly reduced image noise and beam-hardening artifacts when compared with HIR ([image noise, MBIR 3.4 ± 0.7; HIR 2.1 ± 0.8, p < 0.001], [beam-hardening artifacts, MBIR 3.8 ± 0.4; HIR 2.6 ± 1.0, p < 0.001]). CONCLUSIONS: MBIR with a beam-hardening model effectively reduced image noise and beam-hardening artifacts and improved myocardial ECV quantification when compared with HIR using MRI as a reference standard. KEY POINTS: • MBIR with a beam-hardening model effectively reduced image noise and beam-hardening artifacts. • The mean absolute difference between the global mid-ventricular ECV derived from CT and MRI for MBIR was significantly smaller than that for conventional HIR. • MBIR provided more accurate myocardial CT number and improved ECV quantification when compared with HIR.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention With Low-Molecular-Weight Dextran　- Effect on Renal Function.

BACKGROUND: The excessive volume of contrast needed is a significant limitation of optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI). Low-molecular-weight dextran (LMWD) has been used for OCT image acquisition instead of contrast media. This study compared the effects of OCT-guided PCI using LMWD on renal function and clinical outcomes to those of intravascular ultrasound (IVUS)-guided PCI.Methods and Results:In all, 1,183 consecutive patients who underwent intracoronary imaging-guided PCI were enrolled in this single-center, retrospective, observational study. After propensity score matching, 133 pairs of patients were assigned to undergo either OCT-guided PCI using LMWD or IVUS-guided PCI. There was no significant change from baseline in the primary endpoint, serum creatinine concentrations, after the procedure in either group. There were no significant differences between the OCT and IVUS groups in the volume of contrast medium, the incidence of contrast-induced nephropathy (1.5% vs. 2.3%; P=0.65), and major adverse cardiovascular events (MACE) at 30 days (2.3% vs. 6.0%; P=0.12) and 12 months (2.3% vs. 3.0%; P=0.70) after the procedure. Kaplan-Meier analysis at the 12-month follow-up revealed no significant difference in the incidence of MACE between the 2 groups (P=0.75). CONCLUSIONS: OCT-guided PCI using LMWD did not negatively affect renal function and achieved similar short- and long-term clinical outcomes to IVUS-guided PCI.

Temporal Trends in Atherosclerotic Risk Factors in School Children　- Findings From 20-Year Surveillance.

BACKGROUND: Although it has been discussed which measures against atherosclerotic diseases should be started in childhood, the current situation in Japan is unclear.Methods and Results:We conducted a health management survey of all 12-year-old children in a local town for 20 years. The body mass index tended to decrease over time. Although the serum low-density lipoprotein cholesterol level did not change, the levels of serum high-density lipoprotein cholesterol and serum triglycerides significantly increased over time. CONCLUSIONS: The serum triglyceride levels in school children increased significantly, probably through lifestyle changes, and the health management system should be reviewed.