Malarial infection induces tissue hypoxia in the host through destruction of red blood cells. Tissue hypoxia in malarial infection may increase the activity of HIF1α through an intracellular oxygen-sensing pathway. Activation of HIF1α may also induce vascular endothelial growth factor (VEGF) to trigger angiogenesis. To investigate whether malarial infection actually generates hypoxia-induced angiogenesis, we analyzed severity of hypoxia, the expression of hypoxia-related angiogenic factors, and numbers of blood vessels in various tissues infected with Plasmodium berghei . Infection in mice was performed by intraperitoneal injection of 2×10 6 parasitized red blood cells. After infection, we studied parasitemia and survival. We analyzed hypoxia, numbers of blood vessels, and expression of hypoxia-related angiogenic factors including VEGF and HIF1α. We used Western blot, immunofluorescence, and immunohistochemistry to analyze various tissues from Plasmodium berghei -infected mice. In malaria-infected mice, parasitemia was increased over the duration of infection and directly associated with mortality rate. Expression of VEGF and HIF1α increased with the parasitemia in various tissues. Additionally, numbers of blood vessels significantly increased in each tissue type of the malaria-infected group compared to the uninfected control group. These results suggest that malarial infection in mice activates hypoxia-induced angiogenesis by stimulation of HIF1α and VEGF in various tissues.

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Background: Colorectal cancer is one of the most common cancers worldwide. Colorectal cancer that has recurred and metastasized to other organs also has a very poor prognosis. According to recent studies, the long interspersed element-1 (LINE-1) retrotransposon open reading frame (ORF) is located in the intron of the c-Met proto-oncogene, which is involved in cancer progression and metastasis, and regulates its expression. However, no study has compared the expression patterns of LINE-1 ORF1 and c-Met, which are closely related to cancer progression and metastasis, and their correlation in primary and recurrent cancers.Methods: In the present study, we compared the expression patterns of LINE-1 ORF1 and c-Met in both primary and recurrent colorectal cancer tissues from 10 patients. Expression patterns and correlations between LINE-1 ORF1 and c-Met proto-oncogene proteins were analyzed by immunofluorescence staining using both LINE-1 ORF1 and c-Met antibodies.Results: The expression patterns of LINE-1 ORF1 and c-Met showed significant individual differences, and the expression of both proteins was correlated in all colorectal cancer patients. However, the expression levels of LINE-1 ORF1 and c-Met were not significantly different between primary and recurrent colorectal cancers. Conclusions: The protein expression levels of LINE-1 ORF1 and c-Met were correlated, but did not change significantly in cases of recurrent colorectal cancer in the same patient.

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