Preparation and characterization of recombinant human-source collagen / 生物工程学报

This study aimed to obtain a recombinant human-source collagen for industrialization. First, based on the Gly-X-Y sequence of human type I collagen, we optimized the hydrophilic Gly-X-Y collagen peptide, designed the human collagen amino acid sequence and the corresponding nucleotide sequence. Next, the expression vector pPIC9K-COL was constructed via endonuclease digestion technology. We obtained an engineering strain of human-source collagen by electrotransforming Pichia pastoris, and then it was fermented, purified and identified. As a result, the expression level reached 4.5 g/L and the purity was over 95%. After amino acid N-terminal sequencing, molecular weight analysis, amino acid analysis and collagenase degradation test, we confirmed that the obtained collagen was consistent with designed primary structure of human-source collagen. After freeze-drying, we analyzed the collagen by scanning electron microscope and cell cytotoxicity, confirming that the collagen has porous fiber reticular structure and superior cytocompatibility. This indicates that human-source collagen has potential to be applied as biomedical material. In conclusion, we successfully obtained the expected human-source collagen and laid a foundation to its further application.

Prevalence of chronic kidney diseases and associated factors on the basis of stratified random sampling among elderly people in two districts of Jiangsu province, China / 中华肾脏病杂志

Objective To survey the epidemiology of chronic kidney disease (CKD) among elderly people in two districts of Jiangsu province, China. Methods A total of 1404 residents aged 60 years or older in Huaian and Suzhou city in Jiangsu province were randomly recruited from the community population. All the people were screened for albuminuria (increased morning spot urine albumin-to-creatinine ratio, UACR) and reduced renal function (decreased eGFR by simplified MDRD equation). Urinary creatinine and albumin, serum creatinine, uric acid, cholesterol,triglyceride, low density lipoprotein-cholesterol, high-density lipoprotein cholesterol and fasting blood (1.73 m2) -1] and/or albuminuria (UACR ≥30 mg/g). The associations between healthy characteristics and indicators of kidney damage were examined. Results A total of 1316 (93.7%) elderly people completed the study. The prevalence of CKD was 32.3% and the awareness rate was only 9.6%. Albuminuria and reduced renal function were found in 30.2% and 3.2% of subjects respectively. The Logistic regression model showed that age, gender, hypertension,hypercholesterinemia and hyperuricaemia were independently associated with CKD. Systolic blood pressure (SBP) of 140-159 mm Hg exhibited a lower adjusted OR value (0.675) for CKD, while SBP of 160-179 mm Hg and of at least 180 mm Hg exhibited higher adjusted OR values (1.330 and 1.146). Similarly, FBG of 5.6-6.9 mmol/L exhibited a lower adjusted OR value for CKD as compared to FBG of at least 7.0 mmol/L (0.628 vs 1.941). Conclusions The prevalence of CKD in elderly people of Jiangsu province is quite high. Age, gender, hypertension,hypercholesterinemia and hyperuricaemia are independent risk factors for the development of CKD.