Department of Medicine (H7), Karolinska University Hospital, Huddinge, Stockholm, Sweden.
J Intern Med. 2012 Apr;271(4):414-20. doi: 10.1111/j.1365-2796.2011.02441.x. Epub 2011 Sep 2.
Zinc-α2-glycoprotein (ZAG) has been proposed as a tumour-derived cancer cachexia factor. However, ZAG is produced by some normal tissues, including white adipose tissue (WAT), and high serum ZAG levels are present in nonmalignant conditions. We determined whether human WAT contributes to serum ZAG levels and how serum and WAT-secreted ZAG levels correlate with catabolism in patients with cancer and in obese subjects undergoing a very low-calorie diet (VLCD) for 11 days.
DESIGN/SUBJECTS: ZAG levels in serum and in conditioned medium from WAT/adipocytes were determined by enzyme-linked immunosorbent assay. ZAG release from WAT in vivo was determined in 10 healthy subjects. The correlation between ZAG and cachexia was studied in 34 patients with newly diagnosed gastrointestinal cancer. The impact of a VLCD on ZAG release and serum levels was assessed in 10 obese women.
ZAG was released from abdominal WAT and adipocytes in vitro. However, the arteriovenous differences in vivo showed that there was no significant contribution of WAT to the circulating levels. WAT-secreted but not serum ZAG correlated positively with poor nutritional status but not with fat mass (or body mass index) in patients with gastrointestinal cancer. In obese subjects on a VLCD, ZAG secretion from WAT increased significantly whereas serum levels remained unaltered.
ZAG is released from human WAT, but this tissue does not contribute significantly to the circulating levels. WAT-secreted ZAG correlates with nutritional status but not with fat mass in both cancer and nonmalignant conditions. Adipose ZAG is therefore a local factor activated primarily by the catabolic state per se.
锌-α2-糖蛋白（ZAG）被认为是一种肿瘤来源的癌症恶病质因子。然而，ZAG 也由一些正常组织产生，包括白色脂肪组织（WAT），并且在非恶性疾病中存在高血清 ZAG 水平。我们确定人 WAT 是否有助于血清 ZAG 水平，以及血清和 WAT 分泌的 ZAG 水平与癌症患者和接受极低热量饮食（VLCD）11 天的肥胖患者的分解代谢之间如何相关。
设计/受试者：通过酶联免疫吸附试验测定血清和 WAT/脂肪细胞条件培养基中的 ZAG 水平。在 10 名健康受试者中测定体内 WAT 中 ZAG 的释放。在 34 名新诊断为胃肠道癌症的患者中研究 ZAG 与恶病质的相关性。在 10 名肥胖女性中评估 VLCD 对 ZAG 释放和血清水平的影响。
ZAG 从腹部 WAT 和脂肪细胞体外释放。然而，体内动静脉差异表明 WAT 对循环水平没有显著贡献。WAT 分泌但不是血清 ZAG 与胃肠道癌症患者的营养状况差呈正相关，但与脂肪量（或体重指数）无关。在接受 VLCD 的肥胖患者中，WAT 从 ZAG 中释放显著增加，而血清水平保持不变。
ZAG 从人 WAT 释放，但该组织对循环水平的贡献不大。在癌症和非恶性疾病中，WAT 分泌的 ZAG 与营养状况相关，但与脂肪量无关。因此，脂肪 ZAG 是一种主要由分解代谢状态本身激活的局部因子。
