Induction of Angiogenesis by Malarial Infection through Hypoxia Dependent Manner

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 2×10⁶ 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.

Seroprevalence of Antibodies against Anisakis simplex Larvae among Health-Examined Residents in Three Hospitals of Southern Parts of Korea

The present study was performed to estimate the seroprevalence of larval Anisakis simplex infection among the residents health-examined in 3 hospitals in southern parts of Korea. A total of 498 serum samples (1 serum per person) were collected in 3 hospitals in Busan Metropolitan city, Masan city, and Geoje city in Gyeongsangnam-do (Province) and were examined by IgE-ELISA and IgE-western blotting with larval A. simplex crude extract and excretory-secretory products (ESP). The prevalence of antibody positivity was 5.0% and 6.6% with ELISA against crude extracts and ESP, respectively. It was also revealed that infection occurred throughout all age groups and higher in females than in males. A specific protein band of 130 kDa was detected from 10 patients with western blot analysis against crude extract and ESP among those who showed positive results by ELISA. Our study showed for the first time the seroprevalence of anisakiasis in Korea. The allergen of 130 kDa can be a candidate for serologic diagnosis of anisakiasis.

Anisakis simplex Larvae: Infection Status in Marine Fish and Cephalopods Purchased from the Cooperative Fish Market in Busan, Korea

The infection status of marine fish and cephalopods with Anisakis simplex third stage larva (L3) was studied over a period of 1 year. A total of 2,537 specimens, which consisted of 40 species of fish and 3 species of cephalopods, were purchased from the Cooperative Fish Market in Busan, Korea, from August 2006 to July 2007. They were examined for A. simplex L3 from the whole body cavity, viscera, and muscles. A. simplex L3 were confirmed by light microscopy. The overall infection rate reached 34.3%, and average 17.1 larvae were parasitized per infected fish. Fish that recorded the highest infection rate was Lophiomus setigerus (100%), followed by Liparis tessellates (90%), Pleurogrammus azonus (90%), and Scomber japonicus (88.7%). The intensity of infection was the highest in Gadus macrocephalus (117.7 larvae per fish), followed by S. japonicus (103.9 larvae) and L. setigerus (54.2 larvae). Although abundance of A. simplex L3 was not seasonal in most of the fish species, 10 of the 16 selected species showed the highest abundance in February and April. A positive correlation between the intensity of L3 infection and the fish length was obvious in S. japonicus and G. macrocephalus. It was likely that A. simplex L3 are more frequently infected during the spring season in some species of fish. Our study revealed that eating raw or undercooked fish or cephalopods could still be a source of human infection with A. simplex L3 in Korea.