Production of recombinant human growth hormone conjugated with a transcytotic peptide in Pichia pastoris for effective oral protein delivery.

Among the possible delivery routes, the oral administration of a protein is simple and achieves high patient compliance without pain. However, the low bioavailability of a protein drug in the intestine due to the physical barriers of the intestinal epithelia is the most critical problem that needs to be solved. To overcome the low bioavailability of a protein drug in the intestine, we aimed to construct a recombinant Pichia pastoris expressing a human growth hormone (hGH) fusion protein conjugated with a transcytotic peptide (TP) that was screened through peroral phage display to target goblet cells in the intestinal epithelia. The TP-conjugated hGH was successfully produced in P. pastoris in a secreted form at concentrations of up to 0.79 g/l. The function of the TP-conjugated hGH was validated by in vitro and in vivo assays. The transcytotic function of the TP through the intestinal epithelia was verified only in the C terminus conjugated hGH, which demonstrated the induction of IGF-1 in a HepG2 cell culture assay, a higher translocation of recombinant hGH into the ileal villi after oral administration in rats and both IGF-1 induction and higher body weight gain in rats after oral administration. The present study introduces the possibility for the development of an effective oral protein delivery system in the pharmaceutical and animal industries through the introduction of an effective TP into hGH.

[Evaluation of various hepatic lesions with positron emission tomography].

BACKGROUND/AIMS: [18F]FDG-PET is a functional imaging modality reflecting cellular glucose metabolism. In most malignant cells, accumulation and trapping of [18F]FDG allows the visualization of increased uptake compared with normal cells. The aim of this study was to assess the value of PET in differentiating benign from malignant hepatic lesions and to determine in which types of hepatic tumors PET can help evaluate stage, monitor response to therapy, and detect recurrence. METHODS: Eighty patients with liver lesions were enrolled (hepatocellular carcinoma 34, cholangiocarcinoma 8, metastatic liver cancer 25, hemangioma 6, liver abscess 7). Liver metastases were 22 adenocarcinoma, 2 lymphoma, 2 squamous cell carcinoma. The PET images of these patients were analyzed. SUV and lesion-to-normal liver background SUV ratio were obtained and compared among the disease groups. RESULTS: All liver metastases and all cholangiocarcinomas had increased uptake value, with SUV ratios greater than 2. Hepatocellular carcinoma had SUV ratios greater than 2 in 20 of 34 patients (59%). All hemangiomas had poor uptake, a SUV ratio of less than 2. All liver abscesses showed definite uptake. CONCLUSIONS: The PET technique using FDG static imaging was useful in differentiating malignant from benign lesions of the liver in limited situations. Limitations included false negative results in some patients with hepatocellular carcinoma. Liver abscesses raised problems in differential diagnosis from malignant liver tumors. The findings of this study suggest that the PET technique might be applied in tumor staging and the detection of recurrence, as well as monitoring responses to therapy for all adenocarcinomas and some hepatocellular carcinomas.