Preptin 和anti-oxldl 与糖尿病慢性并发症的相关性分析

目的:探讨2型糖尿病患者氧化型低密度脂蛋白抗体(oxldl),preptin水平的变化及其与糖尿病并发症的关系。方法:选择第四军医大学西京医院内分泌代谢科2011年5月至2011年10月住院2型糖尿病患者80例,其中男性53例,女性27例,对患者的慢性并发症检查结果进行评分(方法见下文),总分以5分为界,分为重度并发症40例,轻度并发症40例。正常对照组30例,其中男性17例,女性13例,均检测其血清preptin、anti-oxldl、hsCRP、血脂(lipid)、糖化血红蛋白(HbA1C)、尿微量白蛋白(MAU)、空腹血糖(FBS)、空腹胰岛素(Fins)等水平,并进行各指标之间的相关分析。结果:2型糖尿病患者血清anti-oxldl水平增高,preptin水平降低。二者无相关性。结论:高水平的anti-oxldl和低水平的preptin对糖尿病慢性并发症的发生发展可能有促进作用。     

Synthesis of truncated analogues of preptin-(1–16), and investigation of their ability to stimulate osteoblast proliferation

Preptin, a 34-amino acid residue peptide hormone is co-secreted with insulin from the β-pancreatic cells and is active in fuel metabolism. We have previously established that a shorter fragment of preptin, namely preptin-(1–16), stimulates bone growth by proliferation and increasing the survival rate of osteoblasts. This was demonstrated in both in vitro and in vivo models. These findings suggest that preptin-(1–16) could play an important role in the anabolic therapy of osteoporosis. However, due to the large size of the peptide it is not an ideal therapeutic agent. The aim of this study was to identify the shortest preptin analogue that retains or even increases the bone anabolic activity as compared to the parent preptin-(1–16) peptide. Truncations were made in a methodical manner from both the N-terminus and the C-terminus of the peptide, and the effect of these deletions on the resulting biological activity was assessed. In order to improve the enzymatic stability of the shortest yet active analogue identified, ruthenium-catalysed ring closing metathesis was used to generate a macrocyclic peptide using allylglycine residues as handles for ring formation. We have successfully identified a short 8-amino acid preptin (1–8) fragment that retains an anabolic effect on the proliferation of primary rat osteoblasts and enhances bone nodule formation. Preptin (1–8) is a useful lead compound for the development of orally active therapeutics for the treatment of osteoporosis.     

Three new players in energy regulation: Preptin,adropin and irisin

Homeostasis of energy is regulated by genetic factors, food intake, and energy expenditure. When energy input is greater than expenditure, the balance is positive, which can lead to weight gain and obesity. When the balance is negative, weight is lost. Regulation of this homeostasis is multi-factorial, involving many orexigenic (appetite-stimulating) and anorexigenic (appetite-suppressing) peptide hormones. Peripheral tissues are now known to be involved in weight regulation and research on its endocrine characteristics proceeds apace. Preptin with 34 amino acids (MW 3948 Da), adropin with 43 amino acids and a molecular weight of (4999 Da), and irisin with 112 amino acids (12587 Da), are three newly discovered peptides critical for regulating energy metabolism. Preptin is synthesized primarily in pancreatic beta cells, and adropin mainly in the liver and brain, and many peripheral tissues. Irisin, however, is synthesized principally in the heart muscle, along with peripheral tissues, including salivary glands, kidney and liver. The prime functions of preptin and adropin include regulating carbohydrate, lipid and protein metabolisms by moderating glucose-mediated insulin release. Irisin is an anti-obesitic and anti-diabetic hormone regulating adipose tissue metabolism and glucose homeostasis by converting white to brown adipose tissue. This review offers a historical account of these discovery and function of these peptides, including their structure, and physiological and biochemical properties. Their roles in energy regulation will be discussed. Their measurement in biological fluids will be considered, which will lead to further discussion of their possible clinical value.     

Concentrations of preptin,salusins and hepcidins in plasma and milk of lactating women with or without gestational diabetes mellitus

This study was undertaken to ascertain whether human milk contains preptin, salusin-alpha (salusin-α) and -beta (salusin-β) and pro-hepcidin and hepcidin-25, and whether there are relationships between plasma and milk preptin, salusin-α and -β and pro-hepcidin and hepcidin-25 concentrations in lactating mothers with and without gestational diabetes mellitus (GDM). Blood was obtained from non-lactating women (n = 12), non-diabetic lactating women (n = 12), and GDM lactating women (n = 12). Colostrum, transitional milk, and mature milk samples were collected just before suckling from healthy and GDM lactating women. Peptides concentrations were determined by ELISA and EIA. Mammary gland tissues were screened immunohistochemically for these peptides. Women with GDM had significantly higher plasma and colostum preptin concentrations than healthy lactating women during the colostral and transitional milk period. Salusin-alpha and -beta levels in milk and plasma were lower in women with GDM. Salusin-α and -β were significantly lower in both plasma and colostrums of GDM than of healthy lactating women. Women with GDM had significantly higher colostum prohepcidin and hepcidin-25 concentrations than healthy lactating women during the colostral period. Plasma prohepcidin was also higher in women with GDM than in healthy lactating women during the colostral period, but plasma prohepcidin and hepcidin-25 levels decreased during mature milk period. Transitional milk pro-hepcidin and hepcidin-25 levels in women with GDM were higher than in healthy lactating women. All these results revealed that the mammary gland produces those peptides, which were present in milk at levels correlating with plasma concentrations.