Cultured HCEC established from older donor tissue display greater heterogeneity. The use of HCEC from younger donors may be preferable to maximize the benefits of HCEC transplantation.

Hypoxia occurs during the development of placenta in the first trimester and is implicated in trophoblast differentiation. Intervillous blood flow increases after 10 wk of gestation and results in exposure of trophoblast cells to oxygen. Before this time, low oxygen appears to prevent trophoblast differentiation toward an invasive phenotype. The oxygen-regulated early events of trophoblast differentiation are mediated by TGF-beta3. TGF-beta3 plays a vital role in trophoblast differentiation, and its overexpression can be found in preeclamptic placenta. We sought to determine the mechanism of TGF-beta3 expression through hypoxia-inducible factor (HIF)-1. We show that HIF-1alpha and TGF-beta3 are overexpressed in preeclamptic placenta. Hypoxia not only transactivates the TGF-beta3 promoter activity but also enhances endogenous TGF-beta3 expression. Using the TGF-beta3 promoter deletion mutants, we show that the region between -90 and -60, which contains a putative HIF-1 consensus motif, is crucial for HIF-1-mediated transactivation. Electrophoretic mobility shift assays show that HIF-1 binds to the oligonucleotide containing the HIF-1 motif. Also, introduction of an antisense oligonucleotide for HIF-1 diminishes TGF-beta3 expression during hypoxia, indicating that the up-regulation of TGF-beta3 by hypoxia is mediated through HIF-1. Our results provide evidence that regulation of TGF-beta3 promoter activity by HIF-1 represents a mechanism for trophoblast differentiation during hypoxia.

We report 17 cases of the classic type of Kaposi's sarcoma in Xinjiang, which is located in the north-western area of China surrounded by Mongolia in the east, Russia in the north and Kazakhstan in the west. Fifteen of the patients were of the Uygur people. All patients were male and did not have acquired immunodeficiency syndrome. Most of the lesions were found in the lower and/or upper extremities, with 16 patients showing multiple lesions. Immunohistochemical examination of the lesions revealed that human herpesvirus 8 (HHV-8)-encoded latency-associated nuclear antigen was expressed in the nuclei of spindle-shaped tumor cells. HHV-8 DNA was detected by polymerase chain reaction in all seven cases examined. Phylogenetic tree analysis revealed that DNA sequences of the HHV-8-encoded K1 gene in the seven Kaposi's sarcoma cases were classified as subtype C that was common in the Mediterranean, the Middle East and East Asian countries. In addition, using immunofluorescence we investigated the seroprevalence of HHV-8 in 73 Uygur patients with diseases other than Kaposi's sarcoma. Surprisingly, the serological study revealed that 34 of the patients (46.6%) were positive for antibodies against HHV-8, suggesting that HHV-8 infection is widespread in Xinjiang area. The occurrence of the classic type of Kaposi's sarcoma with a high seropositivity rate implies that Xinjiang is the most endemic area for HHV-8 infection in the world known to date. Considering that Xinjiang is located at the middle point of the Silk Road that used to extend from Rome to China, these data imply that the virus may have been in circulation in this area due to the migration of the people via the Silk Road.