Involvement of Multidrug Resistance-Associated Protein 1 in Intestinal Toxicity of Methotrexate

Purpose  Methotrexate (MTX) causes dose-limiting gastrointestinal toxicity due to exposure of intestinal tissues, and is a substrate of the multidrug resistance-associated protein (MRP) 1. Here we examine the involvement of MRP1, which is reported to be highly expressed in the proliferative crypt compartment of the small intestine, in the gastrointestinal toxicity of MTX. Methods  MTX was intraperitonealy administered to mrp1 gene knockout (mrp1 ^(−/−)) and wild-type (mrp1 ^(+/+)) mice. Body weight, food and water intake were monitored, intestinal histological studies and pharmacokinetics of MTX were examined. Results   mrp1 ^(−/−) mice more severely decreased body weight, food and water intake than mrp1 ^(+/+) mice. Almost complete loss of villi throughout the small intestine in mrp1 ^(−/−) mice was observed, whereas the damage was only partial in mrp1 ^(+/+) mice. Plasma concentration and biliary excretion profiles of MTX were similar in mrp1 ^(−/−) and mrp1 ^(+/+) mice, though accumulation of MTX in immature proliferative cells isolated from mrp1 ^(−/−) mice was much higher compared to mrp1 ^(+/+) mice. Immunostaining revealed localization of Mrp1 in plasma membrane of the intestinal crypt compartment in mrp1 ^(+/+) mice, but not in mrp1 ^(−/−) mice. Conclusion  Mrp1 determines the exposure of proliferative cells in the small intestine to MTX, followed by gastrointestinal toxicity. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Expression of membrane-type 1 matrix metalloproteinase in coronary vessels of allotransplanted primate hearts

BACKGROUND: The mechanisms of intimal thickening in cardiac allograft vasculopathy (CAV) remain controversial after heart transplantation. Matrix metalloproteinase-2 (MMP-2) plays a crucial role in degrading extracellular matrix (ECM) during neointimal formation. Recently, it has been revealed that MMP-2 is activated by membrane-type 1 matrix metalloproteinase (MT1-MMP). This process involves tissue inhibitor of MMP-2 (TIMP-2), forming an MT1-MMP/TIMP-2/pro-MMP-2 complex. In this study, we hypothesize that these components contribute to the pathogenesis of CAV. METHODS: Heterotopic cardiac allografting was performed in randomly paired Japanese monkeys with an immunosuppressive regimen of intravenous administration of antihuman CD18 monoclonal antibody. The donor hearts were harvested at Days 22, 28, 40, 41, and 95 posttransplantation. We examined expression of MMP-2, MT1-MMP, and TIMP-2 of graft vessels using immunohistochemistry and protein level by western blot analysis. RESULTS: Pathologically, various degrees of neointimal formation were observed. In the allografts harvested at Days 22, 28, 40, and 41, MT1-MMP was expressed in the endothelial cells and smooth muscle cells (SMCs) in media of some arteries without histological change, accompanied by expression of MMP-2 and TIMP-2. In the severely thickened neointima of the allograft harvested at Day 95, MMP-2 and faint MT1-MMP were expressed in SMCs of severely thickened neointima and media; TIMP-2 expression was seen only in noncollagenous tissue of severely thickened neointima. MMP-2 protein was more intensely expressed in the allograft harvested at Day 95 than in the allograft harvest at Day 41, while TIMP-2 protein level was almost same in the 2 samples. CONCLUSION: We observed the simultaneous expression of MMP-2, MT1-MMP, and TIMP-2. Thus, ECM degradation triggered by MT1-MMP/TIMP-2/pro-MMP-2 complex could be a novel mechanism of CAV.     

Experience of cerebral angiography using gadolinium for renal insufficiency]

Angiography by means of iodinated contrast material, before endovascular or surgical treatment, may result in serious complications in patients with renal insufficiency or previous anaphylactoid reaction to iodine. Alternative techniques, such as magnetic resonance angiography or carbon dioxide angiography, have their own limitations. We report effectiveness and safety of cerebral angiography using gadolinium for a patient with right vertebral artery and basilar artery occlusion and renal insufficiency. A 66-year-old woman with diabetes under medical treatment suffered loss of consciousness and left hemiparesis following dehydration for 24 hours. She was transferred to our hospital. Emergent MRI suggested brain stem and cerebellar infarction due to vertebral artery occlusion with diffusion-perfusion mismatch. Because of renal insufficiency, the digital subtraction cerebral angiography using gadolinium was performed. Appropriate diagnosis was achieved by angiography using gadolinium of 0.4 mmol/kg. There was no any complication including deterioration of renal function. Gadolinium appears to be a safe and useful intraarterial contrast agent in patients with renal insufficiency.     

Autopsy case of desminopathy involving skeletal and cardiac muscle

Desminopathy is a familial or sporadic skeletal and cardiac muscular dystrophy caused by mutation in the desmin gene. Desmin-reactive deposits in the affected muscles are the morphological hallmarks of this disease. Herein is reported an autopsy case of a 57-year-old Japanese man with adult-onset skeletal muscle weakness and atrioventricular (A-V) conducting block, with a missense A337P mutation in exon 5 of the desmin gene. Disease onset occurred when the patient was 45 years old. The initial presentation was lower limb weakness, and the weakness progressed to the upper limbs. When the patient was 51 years old, a cardiac pacemaker was implanted due to complete A-V block. When the patient was 53 years old, respiratory insufficiency occurred due to weakness of respiratory muscles, and the patient died at the age of 57 years. On autopsy, intrasarcoplasmic desmin-immunoreactive deposits were identified in the skeletal and cardiac muscle, and abnormal accumulations of granulofilamentous material were identified at the ultrastructural level. In the cardiac conducting system, calcification was observed at the bundle of His, and sporadic calcium deposits were observed at the left and right bundle branches.     

Are free radical reactions increased in the diabetic eye?

Reactive oxygen species (ROS) are thought to play a significant role in the development of diabetic retinopathy; however, no direct evidence supports ROS generation in vivo. This study used in vivo electron spin resonance (ESR) spectroscopy with a surface resonator to detect local free radical reactions. The ESR signal decay of carbamoyl-PROXYL was enhanced in the eyes of streptozotocin (STZ)-induced diabetic mice. This enhanced signal decay was suppressed by the administration of SOD or the pretreatment with aminoguanidine. We demonstrate, for the first time, specific free radical reactions in the eyes of mice with STZ-induced diabetes.     

Aquaporin-1 and -5 are involved in the invasion and proliferation of soft tissue sarcomas

Background and aim

Recent studies of several carcinomas have reported that aquaporin possesses novel oncogenic properties. The aim of this study was to clarify the involvement of aquaporin-1 and ?5 in the proliferation, invasion and metastasis of soft tissue sarcomas.

The relationship between lateral displacement of the mandible and scoliosis

Objectives

Idiopathic scoliosis is an orthopaedic disease of childhood, with onset and progress occurring until adolescence. Here, the relationship between lateral displacement of the mandible and scoliosis was analysed quantitatively.

Methods

Seventy-nine non-syndromic Japanese patients (18 men, 61 women), who were diagnosed with jaw deformities and underwent surgical orthognathic treatment at Kyushu University Hospital from January 2011 to August 2014, were enrolled. Their mean age at the time of radiography was 25.3 ± 8.7 years. Postero-anterior cephalometric radiographs and chest radiographs were examined. In postero-anterior cephalometric radiographs, a horizontal baseline (X-axis) was drawn as a straight line that intersects both the zygomatic bases, and a vertical line (Y-axis) was marked perpendicular to the X-axis, with an intersection at the anterior nasal spine (ANS). Point A was defined as the intersection of the X- and Y-axes, and line A was defined as the line connecting point A to the menton. The angle made by the X-axis and line A (i.e., lateral displacement of the mandible) was measured. We designated an absolute value even if the mandibular menton was located on the right or left side. In chest radiographs, Cobb’s method was used to measure scoliosis curves; the direction of the curve was designated similarly.

Results

Nine (11.4%) individuals had a Cobb angle >10°. There was a positive correlation between the Cobb angle and the degree of mandibular deviation (p < 0.05).

Conclusion

Lateral displacement of the mandible and scoliosis are related.

     

Hemodynamic features and impaired arterial oxygenation in patients with portopulmonary hypertension.

Portopulmonary hypertension (P-PHT) is sporadically found in cirrhosis patients who have portal hypertension. We retrospectively investigated the clinical features of six patients with P-PHT and compared their hemodynamics and arterial oxygenation with data from 60 cirrhosis patients without pulmonary hypertension (non-PHT cirrhosis) admitted to our department. The mean pulmonary artery pressure and pulmonary vascular resistance index of P-PHT patients ranged from 25 to 57mmHg and from 399 to 1405dynesscm(-5)m(-2), respectively, and their arterial oxygenation was impaired. The systemic vascular resistance and cardiac index of P-PHT patients were similar level to those of patients with non-PHT cirrhosis. We found 10 patients with non-PHT cirrhosis in whom pulmonary vascular resistance exceeded the critical level for pre-capillary pulmonary hypertension (120dynesscm(-5)). These patients showed a distinctive hemodynamic profile, including a decrease of cardiac output due to contraction of the plasma volume and resultant elevation of systemic vascular resistance. However, the decrease of cardiac output contributed little to the elevation of pulmonary vascular resistance. Our findings suggested that certain factor(s) were acting to raise pulmonary vascular tone in these patients, which might cause chronic damage to the pulmonary vascular bed, leading to the onset of pulmonary hypertension.