BackgroundPulmonary tumor thrombotic microangiopathy (PTTM) has been known as a rare and serious cancer-related pulmonary complication. However, the pathogenesis and pathophysiology of this debilitating condition still remains obscure and no effective management was recommended. The present study aims to elucidate the pathophysiology of PTTM.MethodsAutopsy records were searched to extract cases of pulmonary tumor embolism induced by metastasis of gastric carcinoma in the Toho University Omori Medical Center from 2000 to 2006. And then, tissue sections of extracted cases were prepared for not only light microscopic observation but morphometric analysis with the use of selected PTTM cases.ResultsSix autopsies involved PTTM and clinicopathological data of them were summarized. There was a significant negative association between pulmonary arterial diameter and stenosis rate in four cases. Although all cases showed an increase of stenosis rate to some degree, the degree of stenosis rate varied from case to case. Significant differences were found for average stenosis rate between the under 100 micrometer group or the 100 to 300 micrometer group and the 300 micrometer group in four cases. However, no significant differences were found for average stenosis rate between the under 100 micrometer group and the 100 to 300 micrometer group in all cases. Meanwhile, all cases showed positive reactivity for tissue factor (TF), five showed positive reactivity for vascular endothelial growth factor (VEGF), and three showed positive reactivity for osteopontin (OPN).ConclusionsIn the present study, we revealed that the degree of luminal narrowing of the pulmonary arteries varied from case to case, and our results suggested that pulmonary hypertension in PTTM occurs in selected cases which have a widespread pulmonary lesion with severe luminal narrowing in the smaller arteries. Furthermore, our immunohistochemical examination indicated that gastric carcinoma indicating PTTM shows a higher TF-positive rate than typical gastric carcinoma. However, it remains still obscuring whether gastric carcinoma indicating PTTM shows a higher VEGF or OPN-positive rate as determined by immunohistochemistry.

Numerous reports have shown that psoriasis is associated with obesity and leptin. However, few reports are available on the association between serum leptin levels and leptin gene expression in SAT of psoriasis patients. To clarify this point, we examined serum leptin levels and expression levels of leptin messenger RNA (mRNA) in subcutaneous adipose tissue (SAT) of psoriasis patients. 17 psoriasis vulgaris patients and 6 non-obese control patients who underwent skin surgery were enrolled in this study. We measured serum leptin levels. SAT samples in psoriasis patients were taken from beneath the lesional psoriatic skin at the time of skin biopsy. Leptin mRNA expression in SAT was measured using quantitative real-time reverse transcription polymerase chain reaction (real-time RT-PCR) amplification. Leptin mRNA expression showed a positive correlation with serum leptin levels and BMI. We classified psoriasis patients into two groups according to BMI: the group of non-obese psoriasis patients (BMI < 25, n = 7), and the group of obese psoriasis patients (BMI ≥ 25, n = 10). PASI score, serum leptin levels and Leptin mRNA expression in SAT were significantly higher in the obese psoriasis patients than in the non-obese psoriasis patients. Leptin mRNA expression in SAT was correlated with circulating levels of leptin, the severity of psoriasis, and obesity in psoriasis patients. Serum leptin levels and leptin mRNA expression levels in SAT of non-obese psoriasis patients were not significantly different from those of non-obese controls. The altered secretion of leptin by SAT may be related to the severity of psoriasis.

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