Complement activation in polycystic ovary syndrome occurs in the postprandial and fasted state and is influenced by obesity and insulin sensitivity
CLINICAL ENDOCRINOLOGY
Authors: Lewis, Ruth D.; Narayanaswamy, Anil K.; Farewell, Daniel; Rees, Dafydd Aled
Abstract
Objective Polycystic ovary syndrome (PCOS) is associated with metabolic risk. Complement proteins regulate inflammation and lipid clearance but their role in PCOS-associated metabolic risk is unclear. We sought to establish whether the complement system is activated in PCOS in the fasting and postprandial state. Design Case-control study. Patients Fasting complement levels were measured in 84 women with PCOS and 95 healthy controls. Complement activation post-oral fat tolerance test (OFTT) was compared in 40 additional subjects (20 PCOS, 20 controls). Measurements Activation pathway (C3, C4, C3a(desArg), factor B, factor H, properdin, Factor D) and terminal pathway (C5, C5a, terminal complement complex [TCC]) proteins were measured by commercial or in-house assays. Results Fasting C3, C3a(desArg) and TCC concentrations were increased in insulin-resistant (adjusted differences: C3 0.13 g/L [95%CI 0-0.25]; C3a(desArg) 319.2 ng/mL [19.5-619]; TCC 0.66 mu g/mL [0.04-1.28]) but not in insulin-sensitive women with PCOS. C3 and factor H levels increased with obesity. Post-OFTT, C3 and C4 levels increased to a similar extent in PCOS subjects and controls, whist factor H levels increased more in women with PCOS compared to controls (adjusted differences (area under the curve): 12 167 mu g min/mL [4942-19 392]), particularly in the presence of concomitant obesity. Conclusions Activation and terminal complement pathway components are elevated in patients with PCOS, especially in the presence of insulin resistance and obesity.
Laboratory study on the thermal performance of vertical U-tube ground heat exchanger during short-term borehole thermal energy storage (BTES) and heat extraction process
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
Authors: Wang, Rong; Ni, Long; Yang, Chenlei; Yao, Yang
Abstract
To explore the thermal performance of vertical U-tube ground heat exchanger (GHE) during short-term thermal energy storage (TES) and heat extraction process, a novel and well-controlled sandbox with a plate heat exchanger at the bottom of GHE was proposed and established. According to the experiments of short-term TES and heat extraction under different inlet temperature with Re between 2677 and 2823, we found that the thermal performance of GHE was mainly determined by the dynamic soil temperature distribution around GHE, which was induced by the inlet temperature and operation process of GHE. Furthermore, the energy was concentrated within a limited radius (0.4 m) around the GHE during the 8 hours TES and heat extraction process, which was of benefit to the efficient operation of GHE and the thermal environment of soil. Moreover, compared to the simple extraction process C10 (-/8 degrees C) without TES, the heat extraction process of C5 (35/8 degrees C) obtained a 47.8% increase of average heat extraction rate. In addition, approximately 35% of the injected heat was left in the experimental soil under thermal balance conditions C3, C5, and C7. These results show the superiority and characteristic of short-term TES and heat extraction for GHE operation.